/ Dictionary / Index G guileless: Meaning and Definition of Find definitions for: guile•less Pronunciation: (gīl'lis), [key] — adj. free from guile; sincere; honest; straightforward; frank. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: guileless (Thesaurus) guileful Guilford Related Content Daily Word Quiz: procrastinate Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language