Jeer bishop's mistake (4)
I believe the answer is:
boob
'mistake' is the definition.
(thesaurus)
'jeer bishop's' is the wordplay.
'jeer' becomes 'boo' (I've seen this before).
'bishop' becomes 'b' (abbreviation used in chess).
'boo'+'b'='BOOB'
(Other definitions for boob that I've seen before include "Embarrassing mistake" , "Slip" , "Error" , "Mistake; breast (sl.)" , "Blunder (colloq.)" .)