Careless omission (9)
I believe the answer is:
oversight
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">careless omission</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 oversight that I've seen before include "Failure to notice - blunder" , "A failure to notice, an omission" , "Supervisor's charged with this" , "Neglect" , "act of negligence" .)