Performer rode madly (4)
I believe the answer is:
doer
'performer' is the definition.
(I've seen this in another clue)
'rode madly' is the wordplay.
'madly' is an anagram indicator.
'rode' with letters rearranged gives 'DOER'.
(Other definitions for doer that I've seen before include "Achiever" , "Person of action" , "Martha?" , "energetic person?" , "agent" .)