Offset (10)
I believe the answer is:
counteract
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">offset</span>' is the definition.<br/ ><span class="explanation-format__explanation">(counteracting is a kind of offseting)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for counteract that I've seen before include "Take steps to neutralise" , "Tell against (something)" , "Oppose" , "Nullify" , "Work against" .)