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. [Obs.]

To render sleep's soft blessings insincere.

Syn. -- Dissembling; hollow; hypocritical; deceptive deceitful; false; disingenuous; untrustworthy.

• not sincere
  
• not serious