Blouse exposing back a racy one (9)

I believe the answer is:

garibaldi

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'blouse' is the definition.
(I've seen this before)

'exposing back a racy one' is the wordplay.
'back' suggests the final letters (the letter at the back).
'racy' becomes 'ribald' (I can't explain this - if you can you should give a lot more credence to this answer).
'one' becomes 'i' (Roman numeral).
The last letter of 'exposing' is 'g'.
'g'+'a'+'ribald'+'i'='GARIBALDI'

Can you help me to learn more?

(Other definitions for garibaldi that I've seen before include "Biscuit with currants" , "Italian nationalist; biscuit" , "Revolutionary leader" , "military commander" , "hero in Italy" .)

I've seen this clue in The Daily Express.

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