Stud who calls the shots (4)
I believe the answer is:
boss
'stud' is the definition.
(synonyms)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for boss that I've seen before include "Leader; stud" , "Team manager" , "(One's) chief" , "Stud; chief" , "Informal employer or superior" .)