Container of fuel, perhaps, for military vehicle (4)
I believe the answer is:
tank
This could be a double definition.
'container of fuel' is the first definition.
'tank' can be an answer for 'container' (tank is a kind of container). I am unsure of the 'of fuel' bit.
'for military vehicle' is the second definition.
(tank is a kind of military vehicle)
'perhaps' is the link.
Can you help me to learn more?
(Other definitions for tank that I've seen before include "Water reservoir" , "Military machine" , "Container for fish (or soldiers?)" , "Large container for liquid" , "Large storage chamber" .)