The short way of saying "Fuck you, ow". Depending on the context this phrase has different meanings. Said whilst laughing can express your enjoyment of a friend's humor. Said solemnly can express disappointment in a friend's actions.
Croyden: *Teabags enemy*
Rich: Fuckya *Teabags enemy*
Toni: *Takes a shit (grogan) on friend's lawn* *Takes white t shirt off friend's clothes line*