Stop a bishop with half-cut priest (6)
I believe the answer is:
arrest
'stop' is the definition.
(synonyms)
'a bishop with half-cut priest' is the wordplay.
'bishop' becomes 'rr' (abbreviation for Right Reverend).
'with' says to put letters next to each other.
'half cut' means to take half the letters.
'priest' cut in half is 'est'.
'a'+'rr'+'est'='ARREST'
(Other definitions for arrest that I've seen before include "Stop or slow down the progress of" , "Collar" , "Take into custody as police do" , "Catch" , "Land next to the sea" .)