Cheese he had initially devoured in vehicle (7)
I believe the answer is:
cheddar
'cheese' is the definition.
(I know that cheddar is a type of cheese)
'he had initially devoured in vehicle' is the wordplay.
'he had' becomes 'he'd'.
'initially' says to take the initial letters.
'in' means one lot of letters goes inside another.
'vehicle' becomes 'car' (car is a kind of vehicle).
The initial letter of 'devoured' is 'd'.
'hed'+'d'='hedd'
'hedd' put inside 'car' is 'CHEDDAR'.
(Other definitions for cheddar that I've seen before include "Firm cheese originally from Somerset" , "Somerset gorge location" , "Cheese; Somerset town" , "Gorge with caves - cheese" , "Somerset village" .)