Vehicle returned at eleven (4)
I believe the answer is:
taxi
'vehicle' is the definition.
(I know that taxi is a type of motor car)
'returned at eleven' is the wordplay.
'returned' says the letters should be written backwards.
'eleven' becomes 'xi' (Roman numerals).
'at' reversed gives 'ta'.
'ta'+'xi'='TAXI'
(Other definitions for taxi that I've seen before include "Handgun" , "Part of fleet" , "Prepare to take off" , "Hired vehicle" , "Vehicle with a meter" .)