snigger
verb
[ ˈsnɪɡə ]
• laugh in a half-suppressed, typically scornful way.
• "the boys at school were sure to snigger at him behind his back"
snigger
noun
• a half-suppressed, typically scornful laugh.
• "we heard the sniggers caused by their little jokes"
Origin:
early 18th century: later variant of snicker.