insinceresmile
nounUK /ˌɪnsɪnˈsɪə smaɪl/
US /ˌɪnsɪnˈsɪr smaɪl/
A smile that is not real or true.
She gave an insincere smile to hide her anger.
OTHER MEANINGS
2. A polite but dishonest expression used to be nice without meaning it.
He greeted the new boss with an insincere smile.
3. A smile that hides true feelings like dislike or boredom.
Her insincere smile showed she didn't want to be there.
4. A smile used to flatter or please someone falsely.
The salesman's insincere smile made me distrust him.