1. A term used to describe a man you don't know but is or has been relevant to some aspect of your life.
2. A random guy.
Generally used in a derogatory sense, expressing distaste for the person in question.
Derives from the phrase 'as much/well/good as the next man'.
'So I went to the club expecting to hook-up with Kate but she was there with some next man'
A 'How did you get that black eye?'
B 'I was just minding my own business and got shoved into a wall by this next man, so I got mad and ended up in a fight with him'
'Who's that next man?'