Belligerent, truculent (10)
I believe the answer is:
aggressive
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">belligerent</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >'<span class="explanation-format__original">truculent</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(similar in meaning)</span><br/ ><br/ ></span>
(Other definitions for aggressive that I've seen before include "Pushy" , "Belligerent" , "Rudely hostile" , "Showing anger" , "Vigorous" .)