Monkey or ape (6)
I believe the answer is:
simian
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">monkey</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(thesaurus)</span><br/ ><br/ >'<span class="explanation-format__original">ape</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ ></span>
(Other definitions for simian that I've seen before include "Resembling an ape or monkey" , "Relating to monkeys" , "Of monkeys and apes" , "Primate" , "Monkey-like" .)