Seats not starting to get whiskers (5)
I believe the answer is:
hairs
'whiskers' is the definition.
(I know this)
'seats not starting' is the wordplay.
'seats' becomes 'chairs' (chair is a kind of seat).
'not starting' means to remove the first letter.
'chairs' with its initial letter taken away is 'HAIRS'.
'to get' acts as a link.
(Other definitions for hairs that I've seen before include "Fur filaments" , "See 3" , "Skin growths" , "eg Bristles" , "Threadlike growths" .)