emo

Emo is an abbreviation for 'emotive hardcore punk', or 'emocore', a genre of music and a lifestyle which peaked in the 1990s. Often used nowadays as a classification for people - typically teens - who listen to rock music, are introverted and wear black and maybe have coloured streaks in their hair. Occasionally used as an insult, though emos do not take this as an insult normally.

"Hey, look at him, isn't he an emo?"
"Oh yeah, he's wearing all black and burgundy and listening to Papa Roach."