headbanger

Meanings

1. One who dances by violently shaking the head in time to the music.
2. One who enjoys heavy metal (rock) music, to which this sort of dance is usually performed.
3. A violently deranged, extreme or fanatical person; a nutcase.
4. A silly or eccentric person.
5. A political hardliner, especially an obstructive one.
6. A person who engages in street violence, especially in support of a political group.
7. A kind of chin-up or pull-up exercise where the head is kept in line with the bar.

Etymology

From head + banger.