It has multiple defintitions, Killed, for instance, but also can mean that you're totally f*** up on acid.
To
shout "GET TOASTED!" at someone, for instance, means that you think that
person should eat acid and
kill their egos.
GET TOASTED!! (Eat acid and die!)
Sorry I'm not
going out tonight, I'm totally toasted in my room right
now, petting my fish.
I can't drive right
now I'm way too TOASTED man. I'm TOAST!