hantai is a misspelling of the word hentai which means pervert in japanese. This misspelling is often done by people who act like they don't know what hentai is. Usually these people know alot about anime, hentai porn etc, but
don't want the world to know so they hide it behind
pretending to be stupid. Which such a common used word on
the internet... yeah right...how the heck do you misspell that?