Exact opposite (10)
I believe the answer is:
antithesis
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">exact opposite</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for antithesis that I've seen before include "Contrast between two things" , "Opposite; contrasting idea" , "Direct opposite" , "Reverse" , "I oppose the suggestion" .)