Puritanical when church gets endless credit (7)
I believe the answer is:
ascetic
'puritanical' is the definition.
(thesaurus)
'when church gets endless credit' is the wordplay.
'when' becomes 'as'.
'church' becomes 'ce' (abbreviation for Church of England).
'gets' says to put letters next to each other.
'endless credit' becomes 'tic' (I've seen this in other clues).
'as'+'ce'+'tic'='ASCETIC'
(Other definitions for ascetic that I've seen before include "Frugal" , "Austere disciple" , "One who practises severe selfdenial" , "Self-denying, not allowing oneself luxuries" , "Self-denying, often for religious reasons" .)