Wife leaving joiner for church officer (5)
I believe the answer is:
elder
'church officer' is the definition.
(elder is a kind of church officer)
'wife leaving joiner' is the wordplay.
'wife' becomes 'w'.
'leaving' indicates named letters should be taken away.
'joiner' becomes 'welder' (I have seen 'Joiner of metals ' mean 'welder' so perhaps 'joiner' could also mean 'welder').
'welder' with 'w' taken out is 'ELDER'.
'for' is the link.
(Other definitions for elder that I've seen before include "Tree - wise counsellor" , "Bush" , "comparatively aged" , "Patriarch" , "Tree and Mormon church officer" .)