Miss — neglect (4)
I believe the answer is:
omit
I believe this clue is a double definition.
'miss' is the first definition.
(I know that miss can be written as omit)
'neglect' is the second definition.
(I know that neglect can be written as omit)
(Other definitions for omit that I've seen before include "Leave out, perhaps in error" , "Miss out" , "Leave out or forget" , "Leave out or overlook" , "Leave out or undone" .)