Abate, reduce (6)
I believe the answer is:
lessen
<span class="explanation-format__ClueExplanation">I believe this is a double definition.<br/ ><br/ >'<span class="explanation-format__original">abate</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I know that abate is a more specific form of lessen)</span><br/ ><br/ >'<span class="explanation-format__original">reduce</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I know that reduce is a more specific form of lessen)</span><br/ ><br/ ></span>
(Other definitions for lessen that I've seen before include "Shrink" , "Decrease, diminish" , "decline" , "Contract" , "Become smaller or fewer" .)