The definition of a snigger is a contained or half held-in laugh.
A high-pitched, silly laugh.
To giggle or titter
(Informal) Something amusing, absurd, or contemptible; a joke:
Find another word for titters. In this page you can discover 5 synonyms, antonyms, idiomatic expressions, and related words for titters, like: snickers, sniggers, giggles, twitters and laughs.