Some sausage dogs very old (4)
I believe the answer is:
aged
'very old' is the definition.
(I've seen this before)
'some sausage dogs' is the wordplay.
'some' indicates the answer is hidden within the clue (some of the parts of the word are used).
'AGED' is hidden in the letters of 'sausage dogs'.
(Other definitions for aged that I've seen before include "not like a callow youth" , "Became older" , "Ripened, matured" , "Geriatric" , "Very old, person or wine" .)