The act of being, and acting like a wanker.
Also included, subtle wankerism. The variety of wankerism where people don't understand that you're being a total wanker and taking the piss out of them, until a little while after the said act of wankerism has been performed.
Oh that guy Kim, he says things all the time that appear to be funny, but afterwards you realise he's just being a wanker. He's a master of wankerism.