/ Dictionary / Index T thumb-sucker: Meaning and Definition of Find definitions for: thumb-suck•er Pronunciation: (thum'suk"ur), [key] — n. a person who habitually sucks a thumb. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. thumbstall thumbs-up 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