A person who takes pains in online discussions to point out when someone has made a spelling or grammatical error. This is usually used as an ad hominem attack during an argument, as though spelling and grammar have a bearing on the validity of a statement.

While related to concepts like "grammar nazi", by contrast a "grammerfuck" is not just someone who is strict about spelling and grammar, but someone who actively uses this tactic to attack someone they disagree with, to avoid direct discussion, or to undermine a debate.

The spelling of "grammar" as "grammer" in the word is intentional, to demonstrate how much you don't give a fuck about their rhetorical attack.
Online Conversation:

"You're family is rich, so I think you've got a different perspective on poverty."

"I think you mean 'your'. Maybe you should ask for your college tuition back?"

"Hey, don't be a grammerfuck, how about making an actual point?"
by Jonathan Field February 22, 2008
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