Answer: snigger

AnswerCrossword Clue
SNIGGERSuppressed laugh
SNIGGERDerisive laugh
SNIGGERSubdued laugh.
SNIGGERDerisive sound.
SNIGGERSilly laugh.
SNIGGERSmall laugh
sniggerto snicker (to utter a partly stifled giggle)
sniggersnicker