Son confused as mice ate feline (7,3)
I believe the answer is:
siamese cat
'feline' is the definition.
(Siamese cat is an example)
'son confused as mice ate' is the wordplay.
'son' becomes 's'.
'confused' indicates anagramming the letters.
'as'+'mice'+'ate'='asmiceate'
'asmiceate' with letters rearranged gives 'iamesecat'.
's'+'iamesecat'='SIAMESE CAT'
(Other definitions for siamese cat that I've seen before include "Animal" , "What might be cunning" , "Domestic pet" , "Kitty" , "Feline breed" .)