A douche-bag that listens to crappy music that nobody else likes.
Indie douche-bags often think they know more about music than the average person thus making them cooler. Both facts are usually incorrect.
X: "I liked them before they got big"
Y: "You're such an Indie douche-bag
X: "You've heard of them!?.... there not great"
Y: "You were about to say you love them! Stop being an Indie douche-bag"