Negligent fail again? (6)
I believe the answer is:
remiss
This clue is a double definition.
'negligent' is the first definition.
('remiss' can be similar in meaning to 'negligent')
'fail again?' is the second definition.
('miss' is an answer for 'fail' so perhaps 'remiss' is OK for 'fail again')
(Other definitions for remiss that I've seen before include "Culpable" , "Derelict in duty" , "Failing in what duty requires" , "Neglectful" , "Careless concerning a girl?" .)