GRE Words with Root "in/im/il/ir" (66 words)

About this Root

Core idea: Latin in- assimilates to im-, il-, ir- before certain letters. It can mean in / into / on (incisive, influx) or, for many adjectives, not (incongruous, innocuous)—like Greek a-/an-.

How it shows up on the GRE

Your first step is to decide which in- you have: “in” versus “not.” The root helps—credulous (believing) vs incredulous (not believing). Sentence tone (positive/negative) is a strong check.

Quick hooks from this list

Inchoate — just begun; not fully formed.
Indigenous — native to a place (“born in”).
Inimitable — not able to be imitated.

inadvertent

unintentional

inane

silly; senseless

incendiary

Something capable of causing fire, particularly a weapon.

incense

make angry

incessant

(of something regarded as unpleasant) continuing without pause or interruption.

inchoate

beginning; rudimentary; confused or incoherent

incipient

beginning

incite

stir up; rouse

inconsequential

insignificant

incontrovertible

not able to be denied or disputed.

inculcate

fix firmly by repetition

incumbent

obligatory

incursion

a raid; a sudden attack

indefatigable

(of a person or their efforts) persisting tirelessly.

indeterminate

uncertain

indifferent

apathetic

indigenous

native

indiscriminate

done at random or without careful judgement.

indolent

Habitually lazy, procrastinating, or resistant to physical labor

indomitable

not easily discouraged or subdued

indulgent

inclined to indulge

industrious

diligent and hard-working.

ineffable

to great to be described in words

ineluctable

unavoidable

inept

clumsy

inert

inactive

infuriate

fill with fury or rage

infuse

put; pour; fill

ingenuous

(of a person or action) innocent and unsuspecting.

ingest

take in by swallowing

ingrained

To dye with a fast or lasting colour.

inherent

intrinsic

inhibit

To hold in or hold back; to keep in check; restrain.

inimical

tending to obstruct or harm.

inimitable

defying; imitation; unmatchable

innocuous

not harmful or offensive.

inquest

Legal or judicial inquiry, especially before a jury and especially made by a coroner into the cause of someone.s death

inscrutable

impossible to understand or interpret.

insensible

unconscious

insinuate

to suggest

insipid

Unappetizingly flavorless.

insouciant

unconcerned; carefree

insularity

narrow-mindedness

insurrection

rising of people to open resistance to

interdict

prohibit forbid

interim

as an installment

intermittent

occurring at irregular intervals; not continuous or steady.

intimate

A very close friend.

intractable

unmanageable

intransigence

unwillingness to compromise stubbornness intractability

intrepid

fearless; adventurous (often used for rhetorical or humorous effect).

intrinsic

belonging naturally; essential.

introvert

one who turns towards himself

inundate

To cover with large amounts of water; to flood.

inured

accustomed

invasive

tending to spread very quickly and undesirably or harmfully.

invective

abusive language

inveterate

having a particular habit, activity, or interest that is long-established and unlikely to change.

invidious

Causing ill will, envy, or offense.

invincible

too strong to be defeated

irascible

having or showing a tendency to be easily angered.

irate

angry

ire

anger.

irksome

irritating; annoying.

irresolute

showing or feeling hesitancy; uncertain.

irrevocable

final and unalterable