/ Dictionary / Index I insincere: Meaning and Definition of Find definitions for: in•sin•cere Pronunciation: (in"sin-sēr'), [key] — adj. not sincere; not honest in the expression of actual feeling; hypocritical. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: insincere (Thesaurus) insignificant insincerity Related Content Daily Word Quiz: sequester Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language