Someone who tries to be something that they aren't, esp. when it is at that time considered popular to be part of that specific group or 'clique'. Generally used for fake punks
, or anything associated with rock music.
Hilary Duff pretends to be a punk, when her brand of music is quite recognizably Disney brand pop music
Poser kid: I totally love Green Day! I am like their biggest fan!
Real thing: Cool, what's your favorite song?
Poser kid: Boulevard Of Broken Dreams. Oh my gosh, that is like my theme song.
Real thing: Okay then... do you know any other songs?
Poser kid: Um... isn't that their first hit? They're new.
Real thing: *shakes head and walks away, disgusted*