Air - Nothing / to be ignored: "You got air".
Any - Something insignificant e.g. any girl = someone not important to me.
Bait - Obvious. An indication of dislike: "Nah bruv, that's bait".
Batty - An insulting name for a homosexual man.
Butters - Ugly.
Chattin' breeze - Speaking nonsense.
Chief - Idiot or fool.
Fudge - Stupid. Only got grades F,U,D in their GCSEs
Poomplex - An insult often used in jest.
Rinsed - Over-used, finished.
Screw / screwface - To give someone a dirty look, someone with a nasty/bitchy expression.
Sket - Insult to females, meaning they are sexually promiscuous.
Skits - Mad, from schizo.
Toy - expression of disapproval, meaning bad: "his creps are toy".
Wastegash - Female loser. Sexually promiscuous (sometimes used to mean sexually unavailable).
Wasteman - Mild insult meaning a man who is a loser.

Big - Expression of approval: "Those creps are big".
Bare - Used in place of very or a lot.
Safe - Good. Also used as greeting.
Repping / to rep - Representing, promoting, expressing loyalty to: "Man always reps sarf".