A person who hates something with no constructive reason. If a person has reasons to hate somethings, then he/she is not a hater.
A non-hater: Lil Wayne is garbage because 1. He's lyrics sucks (EX: I bulletproof the ride, now I feel like armadillas), 2. He sounds like a nerdy hobo, 3. He never raps about his expressions, just money, cars, and bitches.
a hater: Immortal Technique sucks because he is garbage.