Someone who cannot use grammar.
Tara Gilebsie-Author of My Immortal Harry Potter Fanfiction, who is Grammatically challenged
by Ginganinja February 20, 2012
A vast majority of the posters on Urban Dictionary.
i dropped out of school when i was four because that bitch teacher was keeping me down, just like the man. STICK IT TO THE MAN! NOW I ARE RACISTSEXIST! ^^ (Grammatically Challenged)
by Moikii September 03, 2007