Judge a rook by vicious dog? (7)

I believe the answer is:

arbiter

'judge' is the definition.
(I know that arbiter is a type of judge)

'a rook by vicious dog?' is the wordplay.
'rook' becomes 'R' (chess abbreviation).
'by' is a charade indicator (letters next to each other).
'vicious dog?' becomes 'biter' (I've seen this in another clue).
'a'+'r'+'biter'='ARBITER'

(Other definitions for arbiter that I've seen before include "Settler of disputes" , "expert" , "He'll decide" , "Judge, umpire" , "Rarebit? (anag)" .)

I've seen this clue in The Sun and the Financial Times.

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