Vehicle I discarded disappeared (8)
I believe the answer is:
vanished
'disappeared' is the definition.
(vanishing is a kind of disappearing)
'vehicle i discarded' is the wordplay.
'vehicle' becomes 'van' (van is a kind of vehicle).
'discarded' becomes 'shed' (I've seen this before).
'van'+'i'+'shed'='VANISHED'
(Other definitions for vanished that I've seen before include "disappeared from view" , "gone" , "disappeared from sight" , "Disappeared without trace" .)