Move back; diminish (6)
I believe the answer is:
recede
<span class="explanation-format__ClueExplanation">I believe this clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">move back</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(receding is a kind of moving back)</span><br/ ><br/ >'<span class="explanation-format__original">diminish</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(thesaurus)</span><br/ ><br/ ></span>
(Other definitions for recede that I've seen before include "Start balding" , "Decline" , "Withdraw" , "Go backwards" , "Go back, ebb" .)