Church officer and laity, not content but getting on (7)
I believe the answer is:
elderly
'getting on' is the definition.
(I've seen this in another clue)
'church officer and laity not' is the wordplay.
'church officer' becomes 'elder' (elder is a kind of church officer).
'and' means one lot of letters go next to another.
'laity not' becomes 'ly' (I am not sure about this - if you are sure you should believe this answer much more).
'elder'+'ly'='ELDERLY'
'content but' acts as a link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for elderly that I've seen before include "Mature" , "Getting on a bit" , "Rather old" , "Past middle age, a senior citizen" , "Long in the tooth" .)