Someone who attempts to understand the nuances of a role-playing system in order to tweak their character to be highly optimized, usually for a single task such as combat.
"Bob is a Minmaxer. The other day i heard him saying:" "Each Agil give +1 attack power, but only while in cat form, so if i get strength gear instead, i can get the bonus while in all forms, but then again i will lose the dodge bonus, but since i wont be tanking this is an acceptable loss and i can squeeze .346 extra dps out of the character....."
A role-playing game player who forgoes making a well-rounded character to make an uber-powerful combat monster. Frequently a player with low self-esteem who is intent on making their character 'better' than the others.
"Yeah, Liz just buffed out Strength and Dexterity and got nothing but combat feats. She's just a minmaxer."