Clothes, left out for Adelaide's friend (6)

I believe the answer is:

cobber

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'friend' is the definition.
(cobber is a kind of friend)

I don't understand how the rest of the clue works.

(Other definitions for cobber that I've seen before include "Antipodean chum" , "Australian term for a pal" , "Mate (Australian)" , "A down-under friend or mate" .)

I've seen this clue in The Times.

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