A word popularized by the teenagers of this generation. It is used to describe someone who is "biting off" another person, and one who tries to fit in with a group. Honestly, no one even gives a shit about who are "posers" and who aren't. In today's logic, any newcomer is a poser, or anyone who decides to wear something else or listen to something else is a poser. The word is used to bash those who try new things regardless of reason for doing so, and it's one of the most overused words by teenagers. It is mostly used by people who have no self-esteem and resort to talking down to other people or friends to satisfy themselves. Seriously people, fuck off already.
Guy #1: Dude, stop wearing LRG, you're such a fucking poser!
Guy #2: Whateva, I do what I want!