Wikipedia:WikiMule

A WikiMule or Equus wikimulus is a user who edits in good faith, but will never admit that they've made a mistake or that they're wrong. Many WikiMules are newcomers who don't have a full grasp on Wikipedia's policies yet.

No matter how many users tell them they're wrong, and no matter how much evidence is presented, they will never admit they're wrong. WikiMules are prone to engaging in edit wars, and kicking with their hooves those who tell them they are wrong. Sometimes they can go as far as making personal attacks and accusing those who disagree of personal attacks, trolling, wikistalking, or even vandalism. Some WikiMules become divas.

Note that a WikiMule, or any user, isn't wrong just because several editors tell them they're wrong. WikiMules can be right. The evidence says more than just the number of editors.