Small vehicle showing damage (4)
I believe the answer is:
scar
'damage' 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'
'showing' acts as a link.
(Other definitions for scar that I've seen before include "It shows where wound was" , "Sign of old injury" , "Fish" , "Mark, blemish" , "Evidence of a past injury?" .)