Code for one not quite in the habit of business (5,6)

I believe the answer is:
smart casual
'business' is the definition.
Both the definition and answer are adjectives.
Perhaps you can see an association between them that I can't see?
I can't explain the remainder of the clue.
Can you help me to learn more?
I've seen this clue in The Independent.
Want a hint initially instead of a full solution?
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