Brand of small vehicle (4)
I believe the answer is:
scar
'brand' is the definition.
(I've seen this before)
'small vehicle' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'vehicle' becomes 'car' (car is a kind of vehicle).
's'+'car'='SCAR'
'of' acts as a link.
(Other definitions for scar that I've seen before include "brand" , "Blemish - cicatrix" , "Mark of healed cut" , "Injury mark - cliff" , "Cicatrice" .)