Up to now endless seat (4)
I believe the answer is:
sofa
'seat' is the definition.
(sofa is a kind of seat)
'up to now endless' is the wordplay.
'up to now' becomes 'sofar' (I've seen this before).
'endless' means to remove the last letter.
'sofar' with its last letter removed is 'SOFA'.
(Other definitions for sofa that I've seen before include "Wide padded seat" , "Comfy piece of furniture" , "Upholstered seat for two or more" , "Area for sitting" , "Upholstered seat for more than one person" .)