Omission (9)
'omission' is the definition.
(oversight is a kind of omission)
This is all the clue.
(Other definitions for oversight that I've seen before include "what supervisor has" , "Mistake resulting from inattention" , "Failure to notice - supervision" , "Failure to notice something" , "error" .)
'omission' is the definition.
(exception is a kind of omission)
This is the entire clue.
(Other definitions for exception that I've seen before include "The one that proves the rule" , "what's against the rules" , "Something that does not follow the rule" , "special case" , "It may be taken after a slight" .)