To laugh with a series of uncontrollable, rapid, high-pitched sounds in a silly or nervous way, as if trying to hold back; titter
To grin is defined as to smile or make an expression that indicates great happiness.
To snicker is defined as to laugh in a stifled way.
(Intransitive) To have (a smile) on one's face.
To sneer is to speak or make an expression that exhibits contempt or mocking.
To set forth in words; state:
Find another word for simper. In this page you can discover 10 synonyms, antonyms, idiomatic expressions, and related words for simper, like: giggle, grin, snicker, smile, sneer, smirk, express, fey, lovesick and prissy.