verb intrans
said of a liquid: to bubble gently below or just at the boiling point
said of food: to cook in a simmering liquid
to develop or ferment
He had ideas simmering in the back of his mind
to be agitated by suppressed emotion
simmering with anger
to cook (food) in a simmering liquid
simmer noun
[alteration of English dialect simper from Middle English simperen, of imitative origin]