Polish saint without pretensions (6)
I believe the answer is:
honest
'without pretensions' is the definition.
(honest can mean simple or unpretentious)
'polish saint' is the wordplay.
'polish' becomes 'hone' (I've seen this before).
'saint' becomes 'st' (abbreviation).
'hone'+'st'='HONEST'
(Other definitions for honest that I've seen before include "Not lying" , "Sincere, truthful" , "Not cheating, just" , "Not dissembling" , "Genuine and trustworthy" .)