General insincerity:
* Paying lip service: This idiom describes someone who expresses agreement or support superficially but doesn't truly believe it.
* Putting on a good face: This means pretending to be happy or content when you are not.
* Talking out of both sides of your mouth: This idiom suggests someone is being contradictory or hypocritical.
* Empty promises: This refers to promises made with no intention of fulfilling them.
* A wolf in sheep's clothing: This metaphor describes someone who appears harmless but is actually deceitful.
Insincerity in speech:
* Smooth talk: This refers to flattering or persuasive language used to deceive someone.
* Sugarcoating: This means making something unpleasant sound more appealing.
* Spinning a yarn: This means telling a lie or a tall tale.
* Giving someone the runaround: This idiom suggests someone is intentionally being evasive or unhelpful.
Insincerity in action:
* Going through the motions: This means performing an action without any real enthusiasm or commitment.
* Fake it till you make it: This phrase describes pretending to have a quality or skill that you don't actually possess.
* Playing the role: This suggests someone is acting insincerely to impress others.
The best idiom to use will depend on the specific context and the type of insincerity you want to describe.