Icba2day means: i cant be arsed to do anything, phonetically spelt: I - see - bea - ay - too - dee - ay, widley used in modernised western countries yet becoming increasing popular in southern Asia and Scotland. The word is usually spoken as an impulsive - spare of the moment expression.
Aron: Do you want to do anything today?
Ebz: Icba2day really!, I'm so tired from last night!
Aron: Haha ok then, I'll ask Dammy to go out!