Young nun is without sin (6)
I believe the answer is:
novice
'young nun' is the definition.
'novice' can be an answer for 'nun' (thesaurus). I'm not sure about the 'young' bit.
'without sin' is the wordplay.
'without' becomes 'no'.
'sin' becomes 'vice'.
'no'+'vice'='NOVICE'
'is' is the link.
Can you help me to learn more?
(Other definitions for novice that I've seen before include "Convert" , "Beginner, trio" , "Probationary monk/nun" , "Person in a religious order who has not yet taken final vows" , "Probationary nun/monk" .)