Responsibility for lapse (9)
I believe the answer is:
oversight
This clue is a double definition.
'responsibility' is the first definition.
(thesaurus)
'lapse' is the second definition.
('oversight' can be a synonym of 'lapse')
'for' acts as a link.
(Other definitions for oversight that I've seen before include "Failure to notice something" , "Innocent mistake" , "what supervisor has" , "Slip-up" , "Neglect" .)