/ Dictionary / Index D doubting Thomas: Meaning and Definition of Find definitions for: doubt'ing Thom'as Pronunciation: [key] a person who refuses to believe without proof; skeptic. John 20:24–29. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. doubtful doubtless Related Content Daily Word Quiz: lyceum Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language