Buff
Buff may refer to any of the following:
1. In computer games, a buff often refers to a bonus given to a game character that extends their ability. A buff is usually gained from an in-game item, another player's ability, or a spell. For example, in the MMORPG (massively-multiplayer online role-playing game) game EverQuest, a popular buff is the SoW (Spirit of Wolf), which increases the movement speed of your character.
The opposite of a buff is a debuff, which decreases a character's attributes or abilities. For example, a mana debuff may reduce the character's overall mana, preventing them from casting as many spells.
2. When a game developer is trying to make a game more balanced they may buff a character, class, or item. If that buff seems like too much they'll nerf it until it seems balanced.