No longer in use (8)
I believe the answer is:
obsolete
'no longer in use' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for obsolete that I've seen before include "Gone out of use and no longer effective" , "Outmoded, passe" , "Pass" , "No longer produced or used" , "Out-of-date" .)