Red motor belonging to me (7)
I believe the answer is:
carmine
'red' is the definition.
(synonyms)
'motor belonging to me' is the wordplay.
'motor' becomes 'car' (informal term for car).
'belonging to me' becomes 'mine' (I've seen this before).
'car'+'mine'='CARMINE'
(Other definitions for carmine that I've seen before include "Crimson pigment" , "Bright red" , "Vivid red colour" .)