Bring up buck (4)
I believe the answer is:
rear
This clue is a triple definition!
'bring' is the first definition.
(thesaurus)
'up' is the second definition.
(thesaurus)
'buck' is the third definition.
(I've seen this before)
(Other definitions for rear that I've seen before include "Raise - back" , "Buttocks - rise up" , "Back; bring up (young)" , "Rump" , "Bring up or stand up on hind legs" .)