Woim is the epitome of bad. It is slang spoken predominantly in south-east London, close to where it originated (Fearghal'z yard). If one is described as 'woim', then there life has no value and they should probably kill themselves.
"No I'm not!"
"Yes you are!"
"Shit you're right. I'm going to rethink my whole life now."
"It's easier to kill yourself"
"Cheers mate, I'll do that then"