Fancy dress functions in circuit clubs, perhaps (8,4)

I believe the answer is:

business suit

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

'fancy dress' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Perhaps there's a link between them I don't understand?

'functions in circuit clubs perhaps' is the wordplay.
'functions in circuit' becomes 'business' (I can't justify this - if you can you should give a lot more credence to this answer).
'clubs perhaps' becomes 'suit' (clubs is a playing card suit).
'business'+'suit'='BUSINESS SUIT'

Can you help me to learn more?

I've seen this clue in The Independent.

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