The passenger food (4)
I believe the answer is:
fare
This clue is a double definition.
'the passenger' is the first definition.
(fare is a kind of passenger)
'food' is the second definition.
(fare is a kind of food)
(Other definitions for fare that I've seen before include "Transport charge" , "Paying passenger" , "(Person paying) price for travel" , "Food for the cost of a journey" , "Food, or price of bus ticket" .)