Mistaken English bishop favoured government (6)
I believe the answer is:
erring
'mistaken' is the definition.
(thesaurus)
'english bishop favoured government' is the wordplay.
'english' becomes 'e' (abbreviation).
'bishop' becomes 'rr' (abbreviation for Right Reverend).
'favoured' becomes 'in' (I've seen this in other clues).
'government' becomes 'g'.
'e'+'rr'+'in'+'g'='ERRING'
(Other definitions for erring that I've seen before include "Going wrong" , "Making 7 down" , "Being incorrect" , "taking wrong direction" , "Sinful" .)