Vehicle to leave its load (5)
I believe the answer is:
cargo
'load' is the definition.
(I know that load can be written as cargo)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for cargo that I've seen before include "Ship's freight" , "Freight, load" , "Stuff on board" , "Load carried" , "Goods being transported" .)