Expressing refusal (8)
I believe the answer is:
negative
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">expressing refusal</span>' is the definition.<br/ ><span class="explanation-format__explanation">('no' is answering in the negative)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for negative that I've seen before include "This required for development" , "Opposite of affirmative" , "Expressing refusal, denial or disagreement" , "Less than zero, minus" , "The photographic film expresses refusal" .)