Naked without a vinaigrette (9)

Ross

I believe the answer is:

undressed

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

I cannot understand how the rest of the clue works.

Can you help me to learn more?

(Other definitions for undressed that I've seen before include "Stripped" , "Exposed" , "Lacking kit" , "Took the clothes off" , "as a plain salad?" .)

I've seen this clue in The Daily Express.

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