Accomplisher (4)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
doer
'accomplisher' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for doer that I've seen before include "Martha?" , "Active type" , "Person of action" , "Active person" , "Achiever" .)