/ Dictionary / Index S sinful: Meaning and Definition of Find definitions for: sin•ful Pronunciation: (sin'ful), [key] — adj. characterized by, guilty of, or full of sin; wicked: a sinful life. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: sinful (Thesaurus) sinfonietta sing 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