Player vs. Player

In Ultima Online, player vs. player (commonly abbreviated PvP) denotes player versus player combat of any kind. Most PvP is centered around the shards of Mugen and Siege Perilous, or the Felucca facet on regular servers.

Terms

Common terms in PvP are:

Perma Red - An obsolete term, it refers to characters who were rendered permanently red because of the rule set in effect at the time ("bouncing" back and forth between red and blue status too many times). Perma Reds are no longer part of the game.
Red - These are Murderers, Player Killers or PKs
Perma Gray - Another obsolete term, it refers to a state thieves would be subject to after a successful steal. 'Perma gray' would only be lieften upon death. While a thief is perma gray, he or she would remain and appear gray only to the person they stole from. And while they would appear blue to everyone else except their victims, they would still be freely attackable by anyone without consequence. A common practice at the time this rule was in effect was to commit suicide intentionally to remove perma gray status. Others include tricking others into thinking you were perma gray in order to have them flag as aggressors, often resulting in a guard whack. Perma grays are no longer part of the game.
Gray - Criminals, Thieves, players who have stolen from an NPC or player, or players who have helped a Red.
Blue - Innocent players and NPCs.
Trammie - A pejorative used to describe characters who do not venture to Felucca and thus do not engage in PvP.

There are also subtypes of PvP as well inside UO.

World PvP - This is PvP that happens for no outher reason that one (or more) people see some one they dont like the look of or whats to be a dick and kill that player over there in fel
Champ PvP - This is when PvP takes place over a champ, this can be one guild is working it and gets raided by a stronger guild after the weaker guild worked it to level 3 or 4 (some times even when the boss is up and redlined).
House PvP - This is one player hides inside a house and attacks people outside the house, mostly seen about yew fel.
Guild Wars - This is when two (or more) guilds hate each outher so much they will request UO to let them go to war, when at war there can be a time limit or kill limit or a war that goes on forever (or intill some one quits).
Faction Wars - This is the oldest form of PvP in UO with a reason to do so. Factions can fight over towns, Holding a town lets them have vendors in that town and set the ammount rate of gold, check out factions on here for more info.