Commonly used by Roadmen in Britain, big man is a term used to tell someone that they are acting bigger than they actually are.
Sometimes you
may hear
people saying “big man ting” in that sense it wouldn’t be used to imply someone isn’t actually a big man but instead is implying that the
person saying “it’s a big man ting” is actually a big man”
Big man means someone who is most likely the leader of the gang.