Boss, hard-working, having debts cancelled (4)
I believe the answer is:
stud
'boss' is the definition.
('stud' can be a synonym of 'boss')
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for stud that I've seen before include "Animal breeding farm" , "Football boot attachment" , "kind of farm" , "Football boot's peg-like projection" , "Wall timber" .)