The most common and most likely answer to this crossword clue is the 6 letter word RUPERT
I've seen this crossword clue in The Guardian
R
U
P
E
R
T
More clues leading to the result RUPERT
- Prince and king entertained by favourite after game
- Fellow is half-rude and cheeky
- Bear being regularly proud and saucy
- Boy in game, forward
- Trapped in ditch there’s a bear
- Man is rugby forward
- Fictional bear from Peru confused by first parts of railway timetable
- Fighting prince, game and jaunty
- Rugby forward, namesake of 10 and half of 1
- Rugby forward finds bear in Nutwood
Buddy explains!

The straight part
We know that "Man" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case man = rupert.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.