Although a small and subtle word, the single utterance of this word will unleash great terror upon the world. For it is the creature that forms when Chuck Norris and Bruce Lee fight each other and form Chuck Lee. Fear him as the dark laugh of death descends upon you.
This word has no inherent meaning but can be used in place of any word (sort of like fuck or smurf: smurf-berries, have a smurfy day, etc).
Chuckle is usually taken to mean the most perverse, obscene, or disgusting thing imaginable in the given context.