1. A person who has a crush on someone but does not show interest, but desperately wants to do so. This usually is the case for the typical nice guy. The word probably derives from the guy who's always in the back who shows interest in a girl but never reveals himself to show interest in her.
1. That guy was totally a backster, I heard from a friend of his friend. He had a major crush on you, he probably didn't want to let you know because you were treating him as a friend.
The opposite of a hipster, a backster is a person who doesn't like things until after they're cool. Also known as slowpoke.
"He's such a backster that he just started watching Arrested Development."
"Hey guys, check out this awesome new band, the Neon Trees!"
1. A person who has a crush on their friend, but their friend has no clue.
2. A friend that has a crush on you without you even knowing, that is, until you find out from other people.
Aang on Avatar is a backster, but since he's smooth, Kitara's going to be all his.