v. to nerf, nerfing, nerfed
to reduce the capabilities of one or more of the player character classes in an MMORPG; performed by the administrators of the game, usu. to restore play balance; the phrase is used with no small degree of derision, and it tends to happen annoyingly often. Ex.: “They nerfed the necromancer’s Feign Death spell again. I’m writing a complaint to Verant, damn it.”
Addendum: Named for the company that produces soft, spongy footballs, baseballs, darts, etc.
Addendum #2: The origin of the term “nerf” was in Ultima Online. When Origin decreased the effectiveness of all weapons across the board, people joked that they had all been given nerf weapons. The term then migrated to EverQuest, since the development team spent more time making characters weaker than doing almost anything else. It’s in pretty common usage for any MMORPG now, though.