Bring up what may be brought up (4)
I believe the answer is:
'be brought up' is the definition.
(I've seen this before)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for rear that I've seen before include "Bring up - back end" , "Posterior" , "Hitchcock film set in one room" , "Bring up or stand up on hind legs" , "Rare at the back" .)