snigger

tirskahdus

tirskua A partly suppressed or broken laugh.
1908, w:Kenneth Grahame|Kenneth Grahame, w:The Wind in the Willows|The Wind in the Willows, page 255,

Here the unfeeling Toad broke into a snigger, and then pulled himself together and tried to look particularly solemn.

(..)presently the Mole's spirits revived again, and he was even able to give some straight back-talk to a couple of moorhens who were sniggering to each other about his bedraggled appearance.