Lack of due care (7)
I believe the answer is:
neglect
'lack of due care' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for neglect that I've seen before include "Fail to attend to properly, task or person" , "lack of concern?" , "Lack of due care and attention" , "Failure to observe" , "Treat carelessly" .)