/ Dictionary / Index T thumbs-up: Meaning and Definition of Find definitions for: thumbs-up Pronunciation: (thumz'up'), [key] — n. Informal. an act, instance, or gesture of assent, approval, or the like. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. thumb-sucker thumbtack Related Content Daily Word Quiz: censure Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language