A person (usually on a forum/newsgroup/chat room) who makes a habit of constantly correcting others' grammatical mistakes, often to the point of annoyance.
Lay off, already! The last thing we need is another fucking grammar nazi!
by Detonate January 06, 2004
1 more definition
person who has a small penis
haha the grammar nazi has a small penis
by The Grammar Nazi January 14, 2003