The type of muscles that develop as a guy transitions from teen/young adult to full fledged man. It is accompanied by a gain in strength and usually happens between the ages of 26-28. Man muscles aren't bigger, but they are rock hard and will allow men to beat much "stronger" young men in things like arm wrestling and give them greater endurance in repetitive hard labor.
You think Bryce Harper is a good player now? Just wait until he gets his man muscles! or Now that LeBron James has his man muscles the rest of the NBA doesn't stand a chance.
Modern term for a top knot, popularised by millionaire footballers who think they're film stars or catwalk models, and copied by hipsters and assorted idiots without a speck of individuality but stupidly think they're being different
Look at that stupid hipster cunt with his man bun, I'd like to set his hair and beard alight, the twat!