Someone who uses you and likes to see you fail in life, school, or even your
job. A big prick, honestly. He maybe uses you to see your
information or something that you own such as a game, car, or maybe even your
own house. He in the end reveals he is your
hater. You then
succeed in kicking the prick in the nose
and breaking a bone.
Dang, Manuel's best friend is a sideline hater, that's just a shame
Josh used to be friends with Garrett until
he found out Garrett
was a sideline hater using him for money, fame, and games. That's super lame.