Discussion Groups / ESL Teaching / November 2003

No, here 'mean coffee' definitely means 'it's a good cup of coffee.'
'Bad coffee', in current usage, almost certainly means exactly what it
sounds like; 'it's a bad cup of coffee'.

From time to time slang usages crop up where an adjective is used
ironically, in more or less the opposite meaning to that given in the
dictionary.

'Bad' to mean 'good' is very late 1980s early 1990s gangster slang -
around the time Michael Jackson made an album called Bad (not to
mention the usage 'a bad mf').  Mean is much more long-lived, going
back decades at least, and still usable.  I'd guess both started as
street terms of respect for tough fighters - someone who's 'mean' (or
'bad') is determined, strong, not to be tangled with, doesn't give up
till the bitter end... a lot like how some people like their coffee!

A similar very current use amongst younger BrE speakers, which I
really like, is 'fierce'

"How was the new club night?"
"Fierce, man."

Such usages are very heavily nuanced and can become very dated very
quickly, and as a non-native speaker you are probably well advised not
to use them to avoid confusion - although you're probably OK with a
'mean cup of coffee'.

Respect
DC Cat