Man staff caught out (4)

I believe the answer is:

rook

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'man' is the definition.
(rook is a kind of man)

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

(Other definitions for rook that I've seen before include "Another name for castle in chess" , "Castle -- bird" , "A bird; overcharge" , "Ringing in the ears" , "Rip off - bird" .)

I've seen this clue in The Telegraph and The Guardian.

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