/ Dictionary / Index T trump card: Meaning and Definition of Find definitions for: trump card Pronunciation: (trump' kärd" for 1 trump' kärd' for 2). [key] trump (def. 1a). something that gives one person or group the advantage over another: The surprise witness was his trump card. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. trump trumped-up Related Content Daily Word Quiz: neologism Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language