Simply a body or corpse of any kind.
Def 2: In some fantasy literature and role-playing game contexts:
A powerful magician who has prolonged his mortal existence beyond natural life (ie. "undeath") and is immune to many human weaknesses.
They bore the farmer's lich through the church gate for burial.
Example of play:
Game Master: Climbing from the sarcofogus you see a somewhat dessicated and decayed form, clad in the vestments of the old Karbanthi order of wizards.
Player 1: Crap! It must be a lich. I told you we shouldn't have come down this far into the dungeon.
Player 2: No problem, my character is a cleric. I cast holy smite on this undead. *player rolls dice* I rolled a 12.
Game Master: *checks lich stats, grins evily* The lich grins and bellows in a distant, echoing voice, "Foolish mortals. I am not some simple zombie your gods can knock down. You stand before Kworzathash greatest of the Karbanthi... and I will eat your souls for disturbing my work.
*deadly combat ensues*
Killmahai1255 just pwned x hero's head for 210 golds.
Killmahai just drew first bloods! (+200 golds)
Killmahai1255 just pwned y hero's head for 210 golds!
Killmahai1256 just got Double Kill!
Killmahai1255 just pwned z hero's head for 210 golds!
Killmahai1256 is on killing spree!
Killmahai1256 just got Triple Kill!
Killmahai1256 (Lich): hahaha!