Discharged from rear into nappy (6)
I believe the answer is:
diaper
'nappy' is the definition.
('diaper' can be a synonym of 'nappy')
'discharged from rear' is the wordplay.
'discharged' becomes 'repaid'.
'from rear' shows that the letters should be reversed in order.
'repaid' backwards is 'DIAPER'.
'into' acts as a link.
(Other definitions for diaper that I've seen before include "type of paving" , "Baby's nappy" , "An American nappy" .)