Endless send-up on organised religion shows persistence (9)
I believe the answer is:
endurance
'persistence' is the definition.
(thesaurus)
'endless send-up on organised' is the wordplay.
'endless' says to take the centre.
'up' becomes 'duce' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'on' is an insertion indicator (as in clothing 'on' a person).
'organised' becomes 'ran' (run can mean to organise or lead).
The central letters of 'send' are 'en'.
'duce' going around 'ran' is 'durance'.
'en'+'durance'='ENDURANCE'
'religion shows' is the link.
This may not be correct. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for endurance that I've seen before include "Ill-fated vessel" , "Stamina" , "Stoical coping with hardship" , "Fortitude" , "Stoical attitude" .)