Slight oversight (7)
I believe the answer is:
neglect
I believe this clue is a double definition.
'slight' is the first definition.
(synonyms)
'oversight' is the second definition.
(I know that oversight can be written as neglect)
(Other definitions for neglect that I've seen before include "Failure to give proper care" , "Not caring" , "Fail to take proper care of, be derelict" , "Fail to care for properly" , "Fail to attend to properly, task or person" .)