impossibility, n. impracticability.

impossible, a. impracticable, unfeasible, unattainable.

impostor, n. pretender, cheat, charlatan, mountebank, quack, deceiver.

imposture, n. fraud, imposition, charlatanism, deception.

impracticability, n. unfeasibility.

impracticable, a. impossible, unfeasible.

impregnate, v. fecundate.

impregnation, n. fecundation.

imprison, v. incarcerate, immure.

imprisonment, n. incarceration, durance, immurement, duress, confinement, commitment.

impromptu, a. improvised, offhand, extempore, extemporaneous.

improper, a. indecorous, unseemly, indecent, inappropriate, wrong, solecistic.

impropriety, n. unsuitableness, unfitness, indecorum, barbarism, solecism.

improve, v. amend, ameliorate, rectify, better, mend; utilize, use; gain, get better.

improvement, n. betterment, amelioration; meliorism; utilization.

improving, a. ameliorative, beneficial, amending.

impudence, n. insolence, impertinence, effrontery, rudeness.

impudent, a. insolent, impertinent, flippant, pert, brazen, saucy.

impulse, n. motive, incentive; impulsion, impetus.

impulsive, a. passionate, capricious, hasty; impellent, propulsive.

impure, a. tainted, defiled, contaminated, polluted, vitiated, infected; adulterated, alloyed, sophisticated; unchaste, lewd, indelicate, indecent; barbarous, vulgar, hybrid.

impurity, n. defilement, contamination, taint, pollution; adulteration, alloy, sophistication; unchastity, lewdness, indecency, indelicacy; pl. garblings, garbles.

inability, n. incompetence, impotence, incapability, incompetency, inefficiency, disability.

in a body. altogether, en masse.

inaccuracy, n. inexactness, incorrectness, impropriety.

inaccurate, a. incorrect, inexact, erroneous, faulty, wrong.

inaction, n. inactivity, inertness, stagnation, idleness.

inactive, a. inert, motionless, quiescent, dormant, inoperative, sluggish, stagnant, dilatory, latent, passive, torpid.

inactivity, n. inaction, passivity, inertia, lethargy, dormancy, stagnation, torpor, latency, sloth, Fabian policy.

inadequate, a. insufficient, deficient; defective, incomplete, imperfect.

inappropriate, a. unsuitable, unbecoming, inapplicable.

inapt, a. irrelevant, unsuitable, inept, inapplicable.

inattention, n. inadvertence, abstraction, heedlessness, disregard, neglect, remissness.

inattentive, a. heedless, absent-minded, inadvertent, unmindful, careless.

inbeing, n. inherence.

inborn, a. congenital, inherent, innate, instinctive, ingenerate.

incapable, a. incompetent, disqualified, unfit, insusceptible.

incarnation, n. incarnification, Avatar; personification.