Favourite hamster? (3)
I believe the answer is:
pet
I believe this clue is a double definition.
'favourite' is the first definition.
(synonyms)
'hamster?' is the second definition.
(I know that pet is a common type of hamster)
(Other definitions for pet that I've seen before include "Favourite, perhaps a domestic animal" , "A dear one exhibits sulkiness" , "blue-eyed boy?" , "Caress - budgie, perhaps?" , "House animal; sulk" .)