Man of defiance (3)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
ian
'man' is the definition.
(man's name)
'of defiance' is the wordplay.
'of' indicates a hidden word.
'IAN' is hidden within 'defiance'.
(Other definitions for ian that I've seen before include "Boy's name (Scottish?)" , "Scottish man's name" , "Male" , "Scottish John" , "- Botham, cricketer" .)