Politely refuse (7)
I believe the answer is:
decline
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">politely refuse</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for decline that I've seen before include "Start to fail" , "Diminish; deteriorate" , "Turn down; deteriorate" , "The classics student must often" , "Become fewer; politely refuse" .)