1) a harsh or humorous critic (sometimes intended as a facetious compliment)
2) a cook who roasts food
3) flesh of a large young chicken over 3 1/2 lb suitable for roasting
4) a special cooking pan for roasting
1) "the honoree gave his roasters as good as he got"
1. The same as lol. Used to express amusement or as a sarcastic comment.
2. A mocking term for Super Smash Bros. Brawl. The term was coined amongst HCSSB Melee players who think Brawl is inferior to Melee. There's presumably also some bitterness involved since Brawl, which is said to have a lower learning curve, was made for everyone and not only the fighting game fans.