a term used to describe a person who is deemed unworthy of attention. e.g. "turn that telly over. Even the sight of thon Juan Simmons would sicken yer happiness"
In Belfast, if you enter a fast food takeaway and ask for a fish supper, the server may well ask "what's ur cawn" in a broad Belfast accent. To which you might reply "fanta". Over the years it has become commonplace to use this phrase as a greeting. So, instead of "what about ye?", you may say "what's ur cawn?".