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.
Pope.
Syn. -- Dissembling; hollow; hypocritical; deceptive deceitful; false; disingenuous; untrustworthy.
© Webster 1913.