5000 Collegiate Words with Brief Definitions – Amass an Ivy League Vocabulary!

mbustible adj. That can not be burned. 
incomparable adj. Matchless. 
incompatible adj. Discordant. 
incompetence n. General lack of capacity or fitness. 
incompetent adj. Not having the abilities desired or necessary for any purpose. 
incomplete adj. Lacking some element, part, or adjunct necessary or required. 
incomprehensible adj. Not understandable. 
incompressible adj. Resisting all attempts to reduce volume by pressure. 
inconceivable adj. Incomprehensible. 
incongruous adj. Unsuitable for the time, place, or occasion. 
inconsequential adj. Valueless. 
inconsiderable adj. Small in quantity or importance. 
inconsistent adj. Contradictory. 
inconstant adj. Changeable. 
incontrovertible adj. Indisputable. 
inconvenient adj. Interfering with comfort or progress. 
indefensible adj. Untenable. 
indefinitely adv. In a vague or uncertain way. 
indelible adj. That can not be blotted out, effaced, destroyed, or removed. 
indescribable adj. That can not be described. 
indestructible adj. That can not be destroyed. 
indicant adj. That which points out. 
indicator n. One who or that which points out. 
indict v. To find and declare chargeable with crime. 
indigence n. Poverty. 
indigenous adj. Native. 
indigent adj. Poor. 
indigestible adj. Not digestible, or difficult to digest. 
indigestion n. Difficulty or failure in the alimentary canal in changing food into absorptive 
nutriment. 
indignant adj. Having such anger and scorn as is aroused by meanness or wickedness. 
indignity n. Unmerited contemptuous conduct or treatment. 
indiscernible adj. Not perceptible. 
indiscreet adj. Lacking wise judgment. 
indiscriminate adj. Promiscuous. 
indispensable adj. Necessary or requisite for the purpose. 
indistinct adj. Vague. 
indivertible adj. That can not be turned aside. 
indivisible adj. Not separable into parts. 
indolence n. Laziness. 
indolent adj. Habitually inactive or idle. 
indomitable adj. Unconquerable. 
induct v. To bring in. 
indulgence n. The yielding to inclination, passion, desire, or propensity in oneself or 
another. 
indulgent adj. Yielding to the desires or humor of oneself or those under one's care. 
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inebriate v. To intoxicate. 
inedible adj. Not good for food. 
ineffable adj. Unutterable. 
inefficient adj. Not accomplishing an intended purpose. 
inefficiency n. That which does not accomplish an intended purpose. 
ineligible adj. Not suitable to be selected or chosen. 
inept adj. Not fit or suitable. 
inert adj. Inanimate. 
inestimable adj. Above price. 
inevitable adj. Unavoidable. 
inexcusable adj. Not to be justified. 
inexhaustible adj. So large or furnishing so great a supply as not to be emptied, wasted, 
or spent. 
inexorable adj. Unrelenting. 
inexpedient adj. Unadvisable. 
inexpensive adj. Low-priced. 
inexperience n. Lack of or deficiency in experience. 
inexplicable adj. Such as can not be made plain. 
inexpressible adj. Unutterable. 
inextensible adj. Of unchangeable length or area. 
infallible adj. Exempt from error of judgment, as in opinion or statement. 
infamous adj. Publicly branded or notorious, as for vice, or crime. 
infamy n. Total loss or destitution of honor or reputation. 
inference n. The derivation of a judgment from any given material of knowledge on the 
ground of law. 
infernal adj. Akin to or befitting hell or its occupants. 
infest v. To be present in such numbers as to be a source of annoyance, trouble, or 
danger. 
infidel n. One who denies the existence of God. 
infidelity n. Disloyalty. 
infinite adj. Measureless. 
infinity n. Boundless or immeasurable extension or duration. 
infirm adj. Lacking in bodily or mental strength. 
infirmary n. A place for the reception or treatment of the sick. 
infirmity n. A physical, mental, or moral weakness or flaw. 
inflammable adj. Easily set on fire or excited. 
inflammation n. A morbid process in some part of the body characterized by heat, 
swelling, and pain. 
inflexible adj. That can not be altered or varied. 
influence n. Ability to sway the will of another. 
influential adj. Having the power to sway the will of another. 
influx n. Infusion. 
infrequence n. Rareness. 
infrequent adj. Uncommon. 
infringe v. To trespass upon. 
infuse v. To instill, introduce, or inculcate, as principles or qualities. 
infusion n. The act of imbuing, or pouring in. 
ingenious adj. Evincing skill, originality, or cleverness, as in contrivance or arrangement. 
ingenuity n. Cleverness in contriving, combining, or originating. 
ingenuous adj. Candid, frank, or open in character or quality. 
inglorious adj. Shameful. 
ingraft v. To set or implant deeply and firmly. 
ingratiate v. To win confidence or good graces for oneself. 
ingratitude n. Insensibility to kindness. 
ingredient n. Component. 
inherence n. The state of being permanently existing in something. 
inherent adj. Intrinsic. 
inhibit v. To hold back or in. 
inhospitable adj. Not disposed to entertain strangers gratuitously. 
inhuman adj. Savage. 
inhume v. To place in the earth, as a dead body. 
inimical adj. Adverse. 
iniquity n. Gross wrong or injustice. 
initiate v. To perform the first act or rite. 
inject v. To introduce, as a fluid, by injection. 
injunction n. Mandate. 
inkling n. A hint. 
inland adj. Remote from the sea. 
inlet n. A small body of water leading into a larger. 
inmost adj. Deepest within. 
innocuous adj. Harmless. 
innovate v. To introduce or strive to introduce new things. 
innuendo n. Insinuation. 
innumerable adj. Countless. 
inoffensive adj. Causing nothing displeasing or disturbing. 
inopportune adj. Unsuitable or inconvenient, especially as to time. 
inquire v. To ask information about. 
inquisition n. A court or tribunal for examination and punishment of heretics. 
inquisitive adj. Given to questioning, especially out of curiosity. 
inquisitor n. One who makes an investigation. 
inroad n. Forcible encroachment or trespass. 
insatiable adj. That desires or craves immoderately or unappeasably. 
inscribe v. To enter in a book, or on a list, roll, or document, by writing. 
inscrutable adj. Impenetrably mysterious or profound. 
insecure adj. Not assured of safety. 
insensible adj. Imperceptible. 
insentient adj. Lacking the power of feeling or perceiving. 
inseparable adj. That can not be separated. 
insidious adj. Working ill by slow and stealthy means. 
insight n. Intellectual discernment. 
insignificance n. Lack of import or of importance. 
insignificant adj. Without importance, force, or influence. 
insinuate v. To imply. 
insipid adj. Tasteless. 
insistence n. Urgency. 
insistent adj. Urgent. 
insolence n. Pride or haughtiness exhibited in contemptuous and overbearing treatment of
others. 
insolent adj. Impudent. 
insomnia n. Sleeplessness. 
inspector n. An official appointed to examine or oversee any matter of public interest or 
importance. 
instance n. A single occurrence or happening of a given kind. 
instant n. A very brief portion of time. 
instantaneous adj. Done without perceptible lapse of time. 
instigate v. To provoke. 
instigator n. One who incites to evil. 
instill v. To infuse. 
instructive adj. Conveying knowledge. 
insufficiency n. Inadequacy. 
insufficient adj. Inadequate for some need, purpose, or use. 
insular adj. Pertaining to an island. 
insulate v. To place in a detached state or situation. 
insuperable adj. Invincible. 
insuppressible adj. Incapable of being concealed. 
insurgence n. Uprising. 
insurgent n. One who takes part in forcible opposition to the constituted authorities of a 
place. 
insurrection n. The state of being in active resistance to authority. 
intangible adj. Not perceptible to the touch. 
integrity n. Uprightness of character and soundness of moral principle. 
intellect n. The faculty of perception or thought. 
intellectual adj. Characterized by intelligence. 
intelligence n. Capacity to know or understand. 
intelligible adj. Comprehensible. 
intemperance n. Immoderate action or indulgence, as of the appetites. 
intension n. The act of stringing or stretching, or state of being strained. 
intensive adj. Adding emphasis or force. 
intention n. That upon which the mind is set. 
interact v. To act reciprocally. 
intercede v. To mediate between persons. 
intercept v. To interrupt the course of. 
intercession n. Entreaty in behalf of others. 
intercessor n. A mediator. 
interdict n. Authoritative act of prohibition. 
interim n. Time between acts or periods. 
interlocutor n. One who takes part in a conversation or oral discussion. 
interlude n. An action or event considered as coming between others of greater length. 
intermediate adj. Being in a middle place or degree or between extremes. 
interminable adj. Having no limit or end. 
intermission n. A recess. 
intermit v. To cause to cease temporarily. 
intermittent adj. A temporary discontinuance. 
interpolation n. Verbal interference. 
interpose v. To come between other things or persons. 
interposition n. A coming between. 
interpreter n. A person who makes intelligible the speech of a foreigner by oral translation.
interrogate v. To examine formally by questioning. 
5000 Collegiate Words with Brief Definitions – Amass an Ivy League Vocabulary! 
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interrogative adj. Having the nature or form of a question. 
interrogatory n. A question or inquiry. 
interrupt v. To stop while in progress. 
intersect v. To cut through or into so as to divide. 
intervale n. A low tract of land between hills, especially along a river. 
intervene v. To interfere for some end. 
intestacy n. The condition resulting from one's dying not having made a valid will. 
intestate adj. Not having made a valid will. 
intestine n. That part of the digestive tube below or behind the stomach, extending to the 
anus. 
intimacy n. Close or confidential friendship. 
intimidate v. To cause to become frightened. 
intolerable adj. Insufferable. 
intolerance n. Inability or unwillingness to bear or endure. 
intolerant adj. Bigoted. 
intoxicant n. Anything that unduly exhilarates or excites. 
intoxicate v. To make drunk. 
intracellular adj. Occurring or situated within a cell. 
intramural adj. Situated within the walls of a city. 
intrepid adj. Fearless and bold. 
intricacy n. Perplexity. 
intricate adj. Difficult to follow or understand. 
intrigue n. A plot or scheme, usually complicated and intended to accomplish something 
by secret ways. 
intrinsic adj. Inherent. 
introductory adj. Preliminary. 
introgression n. Entrance. 
intromit v. To insert. 
introspect v. To look into. 
introspection n. The act of observing and analyzing one's own thoughts and feelings. 
introversion n. The act of turning or directing inward, physically or mentally. 
introvert v. To turn within. 
intrude v. To come in without leave or license. 
intrusion n. The act of entering without warrant or invitation; encroachment. 
intuition n. Instinctive knowledge or feeling. 
inundate v. To fill with an overflowing abundance. 
inundation n. Flood. 
inure v. To harden or toughen by use, exercise, or exposure. 
invalid adj. Having no force, weight, or cogency. 
invalid n. One who is disabled by illness or injury. 
invalidate v. To render of no force or effect. 
invaluable adj. Exceedingly precious. 
invariable adj. Unchangeable. 
invasion n. Encroachment, as by an act of intrusion or trespass. 
invective n. An utterance intended to cast censure, or reproach. 
inveigh v. To utter vehement censure or invective. 
inventive adj. Quick at contrivance. 
inverse adj. Contrary in tendency or direction. 
inversion n. Change of order so that the first shall become last and the last first. 
invert v. To turn inside out, upside down, or in opposite direction. 
investigator n. One who investigates. 
investor n. One who invests money. 
inveterate adj. Habitual. 
invidious adj. Showing or feeling envy. 
invigorate v. To animate. 
invincible adj. Not to be conquered, subdued, or overcome. 
inviolable adj. Incapable of being injured or disturbed. 
invoke v. To call on for assistance or protection. 
involuntary adj. Unwilling. 
involution n. Complication. 
involve v. To draw into entanglement, literally or figuratively. 
invulnerable adj. That can not be wounded or hurt. 
inwardly adv. With no outward manifestation. 
iota n. A small or insignificant mark or part. 
irascible adj. Prone to anger. 
irate adj. Moved to anger. 
ire n. Wrath. 
iridescence n. A many-colored appearance. 
iridescent adj. Exhibiting changing rainbow-colors due to the interference of the light. 
irk v. To afflict with pain, vexation, or fatigue. 
irksome adj. Wearisome. 
irony n. Censure or ridicule under cover of praise or compliment. 
irradiance n. Luster. 
irradiate v. To render clear and intelligible. 
irrational adj. Not possessed of reasoning powers or understanding. 
irreducible adj. That can not be lessened. 
irrefragable adj. That can not be refuted or disproved. 
irrefrangible adj. That can not be broken or violated. 
irrelevant adj. Inapplicable. 
irreligious adj. Indifferent or opposed to religion. 
irreparable adj. That can not be rectified or made amends for. 
irrepressible adj. That can not be restrained or kept down. 
irresistible adj. That can not be successfully withstood or opposed. 
irresponsible adj. Careless of or unable to meet responsibilities. 
irreverence n. The quality showing or expressing a deficiency of veneration, especially for 
sacred things. 
irreverent adj. Showing or expressing a deficiency of veneration, especially for sacred 
things. 
irreverential adj. Showing or expressing a deficiency of veneration, especially for sacred 
things. 
irreversible adj. Irrevocable. 
irrigant adj. Serving to water lands by artificial means. 
irrigate v. To water, as land, by ditches or other artificial means. 
irritable adj. Showing impatience or ill temper on little provocation. 
irritancy n. The quality of producing vexation. 
irritant n. A mechanical, chemical, or pathological agent of inflammation, pain, or tension. 
irritate v. To excite ill temper or impatience in. 
irruption n. Sudden invasion. 
isle n. An island. 
islet n. A little island. 
isobar n. A line joining points at which the barometric pressure is the same at a specified 
moment. 
isochronous adj. Relating to or denoting equal intervals of time. 
isolate v. To separate from others of its kind. 
isothermal adj. Having or marking equality of temperature. 
itinerant adj. Wandering. 
itinerary n. A detailed account or diary of a journey. 
itinerate v. To wander from place to place. 
jargon n. Confused, unintelligible speech or highly technical speech. 
jaundice n. A morbid condition, due to obstructed excretion of bile or characterized by 
yellowing of the skin. 
jeopardize v. To imperil. 
Jingo n. One of a party in Great Britain in favor of spirited and demonstrative foreign policy.
jocose adj. Done or made in jest. 
jocular adj. Inclined to joke. 
joggle n. A sudden irregular shake or a push causing such a shake. 
journalize v. To keep a diary. 
jovial adj. Merry. 
jubilation n. Exultation. 
judgment n. The faculty by the exercise of which a deliberate conclusion is reached. 
judicature n. Distribution and administration of justice by trial and judgment. 
judicial adj. Pertaining to the administration of justice. 
judiciary n. That department of government which administers the law relating to civil and 
criminal justice. 
judicious adj. Prudent. 
juggle v. To play tricks of sleight of hand. 
jugglery n. The art or practice of sleight of hand. 
jugular adj. Pertaining to the throat. 
juicy adj. Succulent. 
junction n. The condition of being joined. 
juncture n. An articulation, joint, or seam. 
junta n. A council or assembly that deliberates in secret upon the affairs of government. 
juridical adj. Assumed by law to exist. 
jurisdiction n. Lawful power or right to exercise official authority. 
jurisprudence n. The science of rights in accordance with positive law. 
juror n. One who serves on a jury or is sworn in for jury duty in a court of justice. 
joust v. To engage in a tilt with lances on horseback. 
justification n. Vindication. 
juvenile adj. Characteristic of youth. 
juxtapose v. To place close together. 
keepsake n. Anything kept or given to be kept for the sake of the giver. 
kerchief n. A square of linen, silk, or other material, used as a covering for the head or 
neck. 
kernel n. A grain or seed. 
kiln n. An oven or furnace for baking, burning, or drying industrial products. 
kiloliter n. One thousand liters. 
kilometer n. A length of 1,000 meters. 
kilowatt n. One thousand watts. 
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kimono n. A loose robe, fastening with a sash, the principal outer garment in Japan. 
kind-hearted adj. Having a kind and sympathetic nature. 
kingling n. A petty king. 
kingship n. Royal state. 
kinsfolk n. pl. Relatives. 
knavery n. Deceitfulness in dealing. 
knead v. To mix and work into a homogeneous mass, especially with the hands. 
knickknack n. A small article, more for ornament that use. 
knight errant n. One of the wandering knights who in the middle ages went forth in search 
of adventure. 
knighthood n. Chivalry. 
laborious adj. Toilsome. 
labyrinth n. A maze. 
lacerate v. To tear rudely or raggedly. 
lackadaisical adj. Listless. 
lactation n. The secretion of milk. 
lacteal adj. Milky. 
lactic adj. Pertaining to milk. 
laddie n. A lad. 
ladle n. A cup-shaped vessel with a long handle, intended for dipping up and pouring 
liquids. 
laggard adj. Falling behind. 
landholder n. Landowner. 
landlord n. A man who owns and lets a tenement or tenements. 
landmark n. A familiar object in the landscape serving as a guide to an area otherwise 
easily lost track of. 
landscape n. A rural view, especially one of picturesque effect, as seen from a distance or 
an elevation. 
languid adj. Relaxed. 
languor n. Lassitude of body or depression. 
lapse n. A slight deviation from what is right, proper, or just. 
lascivious adj. Lustful. 
lassie n. A little lass. 
latent adj. Dormant. 
latency n. The state of being dormant. 
later adv. At a subsequent time. 
lateral adj. Directed toward the side. 
latish adj. Rather late. 
lattice n. Openwork of metal or wood, formed by crossing or interlacing strips or bars. 
laud v. To praise in words or song. 
laudable adj. Praiseworthy. 
laudation n. High praise. 
laudatory adj. Pertaining to, expressing, or containing praise. 
laundress n. Washerwoman. 
laureate adj. Crowned with laurel, as a mark of distinction. 
lave v. To wash or bathe. 
lawgiver n. A legislator. 
lawmaker n. A legislator. 
lax adj. Not stringent or energetic. 
laxative adj. Having power to open or loosen the bowels. 
lea n. A field. 
leaflet n. A little leaf or a booklet. 
leaven v. To make light by fermentation, as dough. 
leeward n. That side or direction toward which the wind blows. 
left-handed adj. Using the left hand or arm more dexterously than the right. 
legacy n. A bequest. 
legalize v. To give the authority of law to. 
legging n. A covering for the leg. 
legible adj. That may be read with ease. 
legionary n. A member of an ancient Roman legion o