Bishop regarding discharge from the back as wonderful (6)
I believe the answer is:
superb
'wonderful' is the definition.
(I know that wonderful can be written as superb)
'bishop regarding discharge from the back' is the wordplay.
'bishop' becomes 'B' (chess abbreviation).
'regarding' becomes 're' (re can mean regarding, concerning).
'discharge' becomes 'pus' (discharge from the body).
'from the back' shows that the letters should be reversed in order.
'b'+'re'+'pus'='brepus'
'brepus' back-to-front is 'SUPERB'.
'as' is the link.
(Other definitions for superb that I've seen before include "Admirable" , "First-class" , "choice" , "Triumphantly effective" , "Terrific" .)