Small motor, crimson, bearing marks (7)
I believe the answer is:
scarred
'bearing marks' is the definition.
(having marks or scars)
'small motor crimson' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'motor' becomes 'car' (informal term for car).
'crimson' becomes 'red' (synonyms).
's'+'car'+'red'='SCARRED'
(Other definitions for scarred that I've seen before include "Blemished" , "Bearing the marks of wounds" , "Flawed" , "Marked for life" , "Marked (by wound)" .)