1.anything you dont know the name for
2.anything disgusting
3.
simile for shit, crap,
turd, and other related words...
i use this word all the time so i would know - i have put alot of effort in this defintition
"whats this chat on the bottom of
my shoe"
"
ooooh, thats chat!"
"
you know that chatness"
"this is the chattest thing i've ever seen mate"