Short for the adjective casually. 'casually - not methodically or according to plan' or 'casually - in an unconcerned manner'
Kishan: Yo ben, do you have strawberries in your fridge?
Ben: yeah bro, casjsh, dont matter though
Kishan: yeh thats casjsh
Ben: yeah bro, casjsh, dont matter though
Kishan: yeh thats casjsh
by Emilton February 09, 2013