WordWeb Online

1. Open and genuine; not deceitful
   "he was a good man, decent and sincere"; "felt sincere regret that they were leaving"; "sincere friendship"
    
2. Characterized by a firm and humourless belief in the validity of your opinions
   "an entirely sincere and cruel tyrant"
   - earnest, solemn

Derived forms: sincerer, sincerest

See also: artless, bona fide, cordial, dear, devout, earnest, echt, existent, genuine, heartfelt, heart-whole, honest, honorable [US], honourable [Brit, Cdn], ingenuous, real, serious, sincerely, sincerity, true, unfeigned, wholehearted, whole-souled

Antonym: insincere

Encyclopedia: Sincere