Wikipedia:Loser

Loser
 * Synonymous with “closer”, usable during a review process when referring to the closer of a discussion.

Discussion
Review discussions, including DRV, MR, and AN, are challenging for the editor who performed the close being reviewed. That editor is typically treated as a loser, and is sometimes referred to as such. Others involved may also lose it.

Of course, review processes serve a critical function of continuous education, and there need be no losers.