Propose kicking bishop's butt (5)
I believe the answer is:
roach
'butt' is the definition.
(I know that roach is a type of butt)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for roach that I've seen before include "Trim" , "Historic SE county" , "Small freshwater fish related to carp" , "butt" , "Fish of the carp family" .)