Fail to care for (7)
I believe the answer is:
neglect
'fail to care for' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for neglect that I've seen before include "Ignore" , "Fail to pay due attention to (7)" , "Leave unattended, disregard" , "Fail to act or take care" , "Disuse" .)