A Gaming Glossary: O – The Minmax Papers

1) Overpowered; too powerful compared to other options. A character, item, or build is said to be OP if it confers an unfair or excessive advantage. If enough people feel that something is OP, they will often petition the game’s developer to nerf it. The less common antonym of OP is UP (underpowered).
Rogues are incredibly OP and Blizz needs to nerf them.

2) (forums, social media) Original poster; the person who started a discussion thread.
Why are we talking about Sorceress? OP clearly asked for advice on Druid builds.