/ Dictionary / Index I impossible: Meaning and Definition of Find definitions for: im•pos•si•ble Pronunciation: (im-pos'u-bul), [key] — adj. not possible; unable to be, exist, happen, etc. unable to be done, performed, effected, etc.: an impossible assignment. incapable of being true, as a rumor. not to be done, endured, etc., with any degree of reason or propriety: an impossible situation. utterly impracticable: an impossible plan. hopelessly unsuitable, difficult, or objectionable. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: impossible (Thesaurus) impossibility impost Related Content Daily Word Quiz: spectral Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language