Mental lapse (10)
I believe the answer is:
aberration
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">mental lapse</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for aberration that I've seen before include "moral lapse" , "Mental lapse" , "Deviation from normality" , "Deviation from the accepted norm" , "Unwelcome deviation from normal" .)