A word that originated in liverpool which was originally used to describe someone who drank meths... now however it means something completely different that is hard to put your finger on. Its a insult but not, kind of like a ditsy idiot. someone who doesnt quite fit in, has the wrong brands... but again still hard to explain...
'my trainers are nicks' 'aw man thats well meffy! you meff'
'my mum shops at nettos' you total meff'
'says something stupid, like england will float if theres global warming coz were an island' omg how stupid are you you f*****ing meff!'