A pretentious person who thinks s/he is cultured and often superior to others simply because s/he listens to indie music, watches art films, and drinks overly expensive coffee at coffee houses that are often crowded with other hipsters. Most often they possess an economically worthless degree in something like philosophy, liberal arts, or history that they earned at a junior college or satellite university. They waste most of their disposable income on albums, cigarettes, and/or going to crappy shows. They often follow issues surrounding liberal topics and are typically very liberal themselves, often to the point of being very narrow-minded (though they think they're the most open-minded people). They delude themselves to the point of thinking they're more refined than everyone else when they're really just pseudo-intellectuals who need to stop wearing used clothing and take showers more often.
That hipster in my creative writing class always criticizes my poems. That $6 coffee he gets every morning must be rotting his brain.