Crossword Genius

Nun dressing might thus form behaviour pattern (3,4,3,5)

Ross

I believe the answer is:

get into the habit

I'm a little stuck... Click here to teach me more about this clue!

'nun dressing might thus form behaviour' is the definition.
I know nothing about this answer so I can't judge whether it can be defined by this definition.

'pattern' is the wordplay.
I cannot quite see how this works, but
'pattern' could be 'habit' (habit is a kind of pattern) and 'habit' is located in the answer.
This may be the basis of clue (or it may be nonsense).

Can you help me to learn more?

I've seen this clue in the Sydney Morning Herald.
Want a hint initially instead of a full solution? Install my app