mosh

Etymology

Possibly an alteration or deformation of mash.

verb

1. (intransitive) To dance by intentionally jumping into and colliding with other, similarly behaving dancers, and performing other wild, aggressive, or spastic movements.
   From 9 in the morning (when It Dies Today played the lot) until 9 at night (when Ozzy Osbourne led Black Sabbath on the main stage), hardy fans cheered and moshed and staggered through a stifling but often exciting day. 2005 July 28, Kelefa Sanneh, “Heat, Good Cheer, Jagged Music and Even Some Melody”, in New York Times
2. (transitive) To intentionally jump into and collide with another, similarly behaving dancer at a concert.

noun

1. The moshing style of dancing.
   We had a great mosh at the gig.