Knog or knogger is someone trying to be cool but getting it all wrong.
Adapted from an uncool typo of "It's on like donkey kong" to "donkey knog". A piss take use of this term has rapidly expanded through the south east of England to replace words like c**t, idiot, muppet, wally etc.
That guy is such a knog or knogger etc.
Please add more if you hear them.