Gamble involving a man - a titled man (7)
I believe the answer is:
baronet
'a titled man' is the definition.
(I've seen this before)
'gamble involving a man' is the wordplay.
'gamble' becomes 'bet' (bet is a kind of gamble).
'involving' is an insertion indicator.
'a man' becomes 'aron' ().
'bet' going around 'aron' is 'BARONET'.
(Other definitions for baronet that I've seen before include "Nobleman" , "Minor title" , "Lowest British hereditary title" , "Member of the British order of honour" , "Lower noble" .)