Front vehicle (3)
I believe the answer is:
van
This clue is a double definition.
'front' is the first definition.
(I've seen this in other clues)
'vehicle' is the second definition.
(van is a kind of vehicle)
(Other definitions for van that I've seen before include "Commercial vehicle in the lead?" , "Covered wagon" , "Commercial vehicle at head of army" , "Commercial vehicle or front of army" , "Leading unit at the head of an army" .)