Stud (4)
I believe the answer is:
boss
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">stud</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for boss that I've seen before include "Domineer" , "One in charge; stud" , "27 [CHIEF]" , "Person managing" , "Informal employer or superior" .)