Moral fall (5)
I believe the answer is:
lapse
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">moral fall</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 lapse that I've seen before include "Sepal (anag)" , "Temporary failure of judgment or concentration" , "Backslide" , "Loss (in concentration, say?)" , "Slight error as caused by inattention" .)