Soothe, calm (6)
I believe the answer is:
pacify
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">soothe</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >'<span class="explanation-format__original">calm</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(pacifying is a kind of calming)</span><br/ ><br/ ></span>
(Other definitions for pacify that I've seen before include "Mollify, appease" , "Make calm, soothe" , "Quieten" , "Quell the anger of" , "Make calm, appease" .)