The most common and most likely answer to this crossword clue is the 5 letter word BEING
I've seen this crossword clue in The Times
B
E
I
N
G
Buddy explains!

The straight part
We know that "Man maybe" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case man maybe = being.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.
What does BEING mean?
BEING noun- A living creature.
- The state or fact of existence, consciousness, or life, or something in such a state.
- That which has actuality (materially or in concept).
- One's basic nature, or the qualities thereof; essence or personality.
- An abode; a cottage.
- Given that; since.