Vagrant seen before parking vehicle (5)
I believe the answer is:
tramp
'vagrant' is the definition.
(I've seen this in another clue)
'before parking vehicle' is the wordplay.
'before' says to put letters next to each other.
'parking' becomes 'p' (abbreviation on road signs).
'vehicle' becomes 'tram' (tram is a kind of vehicle).
'p' put after 'tram' is 'TRAMP'.
'seen' is the link.
(Other definitions for tramp that I've seen before include "Derelict - ship" , "Vagrant, drifter" , "Tread heavily (on)" , "Walk heavily - steamer" , "Live as a vagrant" .)