In′sin‐cere″ (?), a. [L. insincerus. See In- not, and Sincere.]
1. Not being in truth what one appears to be; not sincere; dissembling; hypocritical; disingenuous; deceitful; false; — said of persons; also of speech, thought; etc.; as, insincere declarations.
2. Disappointing; imperfect; unsound.
To render sleep's soft blessings insincere. Pope.
Syn. — Dissembling; hollow; hypocritical; deceptive deceitful; false; disingenuous; untrustworthy.