To purse your lips is to press them together in disapproval. Purse your lips and say nothing.
It says what the person has decided not to say, which everybody in the room understands. To purse your lips makes the mouth the shape of a bag drawn shut with a string.
1phrasepurse your lipsTo press the lips together in disapproval.
“She would purse your lips rather than criticise anybody out loud.”
purse your lips is a gesture.
Practised in Body Language & Gestures