Feel sorry (6)
I believe the answer is:
regret
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">feel sorry</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for regret that I've seen before include "Bad feeling" , "Rue, repent" , "Feel remorse for" , "Rue, repine" , "Be sorry for, wish it hadn't happened" .)