Wiktionary
piss artist
n. 1 (context British slang English) Someone who is frequently drunk (pissed.) 2 (context British slang English) Someone who claims knowledge or understanding that he does not possess. 3 (context British slang English) Someone who frequently ridicules others (take the piss)
Usage examples of "piss artist".
You're a fucking piss artist at the moment, but you're still a clever man.
Seb would have no difficulty finding another job, but, at fifty-one and a notorious piss artist, Charles was far more of a problem.