Not bad habit in a junior (6)
I believe the answer is:
novice
'a junior' is the definition.
The definition and answer can be both people as well as being singular nouns.
Perhaps you can see a link between them that I can't see?
'not bad habit' is the wordplay.
'not' becomes 'no' (negative).
'bad habit' becomes 'vice' (a sin or weakness).
'no'+'vice'='NOVICE'
'in' is the link.
Can you help me to learn more?
(Other definitions for novice that I've seen before include "Acolyte" , "New member (of religious order)" , "apprentice" , "Beginner as in religious order" , "Beginner, perhaps at religious orders" .)