Ferocious, brutal (6)
I believe the answer is:
savage
<span class="explanation-format__ClueExplanation">I believe this clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">ferocious</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >'<span class="explanation-format__original">brutal</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ ></span>
(Other definitions for savage that I've seen before include "Cruel, vicious" , "Uncivilized" , "Fierce, cruel" , "Wild, untamed" , "Wild and menacing" .)