A word that originated in a Sydney eastern suburbs private school from a combination of the words chat, shame and anus. In addition to being a suitable synonym for all of its root words, the word can also be used in a variety of other contexts. The word is primarily used as a replacement for the word bullshit or the phrase yeah right.
"Oi mate, that chick said she wants to go out with you... chamus!"
"That was the most chamus food I've ever tasted."
"Yeah chamus you think that you could beat me up."