English bishop caught in seedy joint (5)
I believe the answer is:
elbow
'joint' is the definition.
(joint of the body)
'english bishop caught in seedy' is the wordplay.
'english' becomes 'e' (abbreviation).
'bishop' becomes 'B' (chess abbreviation).
'caught in' means one lot of letters goes inside another.
'seedy' becomes 'low' (both can sordid).
'b' going within 'low' is 'lbow'.
'e'+'lbow'='ELBOW'
(Other definitions for elbow that I've seen before include "Sharp bend in a road or river" , "Reject" , "Below (anag.)" , "Dismissal?" , "Arm joint, more power to it" .)