PvP
From HollowWiki
PvP means to "Player Versus Player" duel someone. This refers to when players engage in combat using the duel command. Players may fight each other in PvP for experience and treasure. However, repeat PvPing of a player is considered harassment, as is waiting at the player's spawn site to kill them over and over.
A battle between two players in this fashion is sometimes called a PvP duel.
See Also;