Vehicle offering endless concern (3)
I believe the answer is:
car
'vehicle' is the definition.
(I've seen this before)
'endless concern' is the wordplay.
'endless' means to remove the last letter.
'concern' becomes 'care' ('care' can be a synonym of 'concern').
'care' with its final letter taken off is 'CAR'.
'offering' is the link.
(Other definitions for car that I've seen before include "Hatchback, say?" , "Road vehicle; rail coach" , "One for the road?" , "Means of transport" , "Automobile" .)