Vehicle that's brown and khaki primarily? (4)
I believe the answer is:
tank
'vehicle' is the definition.
(tank is a kind of vehicle)
'brown and khaki primarily?' is the wordplay.
'brown' becomes 'tan' (tan is a kind of brown**).
'and' means one lot of letters go next to another.
'primarily?' says to take the initial letters (I've seen 'primarily' mean this).
The first letter of 'khaki' is 'k'.
'tan'+'k'='TANK'
'that's' acts as a link.
(Other definitions for tank that I've seen before include "defeat" , "Army vehicle - reservoir" , "Armoured vehicle; large container" , "Military vehicle (for fish?)" , "Container for fish (or soldiers?)" .)