Detailed research into boss (4)
I believe the answer is:
stud
'boss' is the definition.
(synonyms)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for stud that I've seen before include "Dot" , "sort of stable" , "who believes he can keep it up" , "Sexual athlete" , "Football boot's peg-like projection" .)