Peer losing case, every twelve months (4)

I believe the answer is:

earl

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'peer' is the definition.
(I know that earl is a type of peer)

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

(Other definitions for earl that I've seen before include "Peer (Br.)" , "British noble" , "Noble title" , "A real titled lord" , "British nobleman" .)

I've seen this clue in The Independent.

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