Using over exaggerated poor use of grammar to highlight a joke in an internet chat room. Usually AntiGrammar sentences don't make much sense and should be somewhat hard to decipher, but still readable.
Oh em geeu suk. fuku. I luv vidjyo gayms and plhay dem awl dai long. Eye youse Antigrammar cuz eye ham kewl.
Like an auntie and a grandma all rolled into one. Your bestie’s grown child has a baby. That baby calls you auntie-gram. All the fun, none of the responsibility.