Religious leader in prison over debts (5)
I believe the answer is:
pious
'religious' is the definition.
(associated in meaning)
'leader in prison over debts' is the wordplay.
'leader in' indicates taking the first letters.
'over' means one lot of letters go next to another.
'debts' becomes 'IOUs' (I've seen this in another clue).
The initial letter of 'prison' is 'p'.
'p'+'ious'='PIOUS'
(Other definitions for pious that I've seen before include "Godly" , "Devoutly religious" , "Holier-than-thou" , "Saintly" , "God-fearing" .)