Farrow back in goal (3)
I believe the answer is:
aim
'goal' is the definition.
(aim is a kind of goal)
'farrow back' is the wordplay.
'farrow' becomes 'mia' (I've seen this in another clue).
'back' says the letters should be written backwards.
'mia' backwards is 'AIM'.
'in' is the link.
(Other definitions for aim that I've seen before include "Set sights on, target or goal" , "Set sights on, say target" , "Plan" , "Steady, ... fire" , "Draw a bead on" .)