Punish favourite dog (7)

I believe the answer is:

whippet

'dog' is the definition.
(whippet is a kind of dog)

'punish favourite' is the wordplay.
'punish' becomes 'whip' (I've seen this before).
'favourite' becomes 'pet' (synonyms).
'whip'+'pet'='WHIPPET'

(Other definitions for whippet that I've seen before include "Racing-dog" , "dog class?" , "Small greyhound-type dog" , "Dog bred for racing" , "Dog similar to a greyhound" .)

I've seen this clue in The Independent, The Times and The Sun.

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