adjective

insincere

in-sin-SEER/ˌɪnsɪnˈsɪr/

Not expressing genuine feelings, beliefs, or intentions.

The woman's congratulations are insincere, contradicted by her hidden thumbs-down gesture.

A woman smiles warmly and shakes a prizewinner’s hand while concealing an emphatic thumbs-down behind her back, visibly contradicting her congratulatory manner.
Etymology

Sincerus described things as pure or unmixed and, figuratively, people as genuine or truthful. Adding “not” gives the idea of feelings or statements adulterated by pretense rather than honestly expressed.

In context

Smarter While You Sleep16:46
Empty flattery or overly exaggerated praise can often come across as insincere,
100 Savage Psychology Tricks That Give You Unfair Control

More examples

  • She recognized the insincere praise immediately.
  • He gave an insincere promise merely to end the argument.
  • Their friendly manner concealed an insincere offer of help.

Forms

insincere · more insincere · most insincere

insincerity noun — a lack of genuine feeling or belief

Similar words

false
False broadly means untrue; insincere specifically means not expressing one’s real feelings or beliefs.
hypocritical
Hypocritical involves a gap between professed values and behavior; insincere can concern any untruthful expression of feeling.