Dominant individual (3,3)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">dominant individual</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for top dog that I've seen before include "Leader of a group" , "big cheese?" , "One pre-eminent in their field" , "Boss" , "Thirteen [HONCO]" .)