Being brave, is now returning to the arena (6)
I believe the answer is:
daring
'being brave' is the definition.
(I've seen this before)
'now returning to the arena' is the wordplay.
'now' becomes 'ad' (I've seen this in other clues).
'returning' says the letters should be written backwards.
'to the arena' becomes 'ring' (I've seen this in other clues).
'ad' written backwards gives 'da'.
'da'+'ring'='DARING'
'is' acts as a link.
(Other definitions for daring that I've seen before include "'Adventurous, bold (6)'" , "Audacious, bold" , "Audacity" , "Derring-do" , "Adventurous courage" .)