Goof up (3)
I believe the answer is:
err
'goof up' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for err that I've seen before include "'To . . . is human, to forgive divine'" , "Slip up" , "Make mistakes" , "'to... is human,to forgive divine'" , "Go astray" .)