Potwash - someone/something that is useless, pointless. Derived from the job 'potwash' in which someone who works in a pub/restaurant and only 'washes the pots'.
Calling someone or something a potwash could mean they are stupid, useless, meaningless, pointless, dumb, worthless etc.
The word originated at Chichester University, West Sussex, United Kingdom, December 2012
1. *someone breaks something
'Oh my you are such a potwash Soph!'
2. *someone does a job/task wrong
'Chris you're nothing but a potwash!'
3. 'That lesson was so pointless'
'Yeah, it was absolute potwash!'
4. 'You're an idiot!'