Fan removes uniform for closest mate (4)

I believe the answer is:

buff

'fan' is the definition.
(I know that fan can be written as buff)

I can't explain the rest of the clue.

(Other definitions for buff that I've seen before include "nude?" , "Yellowish colour - polish - expert" , "Polish; expert, devotee" , "Polish; yellowish-beige" , "Dull brownish-yellow - expert" .)

I've seen this clue in The Guardian and The Irish Times.

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