Top end on motor (6)
I believe the answer is:
cardie
'top' is the definition.
(short for cardigan)
'end on motor' is the wordplay.
'end' becomes 'die' ().
'on' is a charade indicator (letters next to each other).
'motor' becomes 'car' (informal term for car).
'die' after 'car' is 'CARDIE'.
(Other definitions for cardie that I've seen before include "Knitted jacket that buttons up the front (abbr)" , "Jumper (colloq.)" .)