Mistake made by English bishop over gold (5)
I believe the answer is:
error
'mistake' is the definition.
('error' can be a synonym of 'mistake')
'english bishop over gold' is the wordplay.
'english' becomes 'e' (abbreviation).
'bishop' becomes 'rr' (abbreviation for Right Reverend).
'over' means one lot of letters go next to another.
'gold' becomes 'or' ('or' is the heraldic name for gold).
'e'+'rr'+'or'='ERROR'
'made by' is the link.
(Other definitions for error that I've seen before include "Slip, mistake" , "Faulty judgement" , "Mistake, lapse" , "Blunder, slip" , "Faulty judgment" .)