Bring up back (4)
I believe the answer is:
rear
This clue is a double definition.
'bring up' is the first definition.
(as in rearing children)
'back' is the second definition.
(something's rear is its back)
(Other definitions for rear that I've seen before include "early, long before now" , "Back; bring up (young)" , "Jump" , "Bring up - the tail" , "what you may bring up" .)