/ Dictionary / Index P preposterous: Meaning and Definition of Find definitions for: pre•pos•ter•ous Pronunciation: (pri-pos'tur-us, -trus), [key] — adj. completely contrary to nature, reason, or common sense; absurd; senseless; utterly foolish: a preposterous tale. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: preposterous (Thesaurus) prepossession prepotency Related Content Daily Word Quiz: deleterious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language