Small vehicle making permanent mark (4)
I believe the answer is:
scar
'permanent mark' 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'
'making' is the link.
(Other definitions for scar that I've seen before include "Mark left by the healing of injured tissue" , "reminder of sword-fight?" , "Mark left by injury" , "Effect of unpleasant experience" , "A bare precipice" .)