Cold in truck in the far north (6)
I believe the answer is:
arctic
'in the far north' is the definition.
(near the North Pole)
'cold in truck' is the wordplay.
'cold' becomes 'c' (eg on taps).
'in' indicates putting letters inside.
'truck' becomes 'artic' (short for articulated lorry).
'c' inserted inside 'artic' is 'ARCTIC'.
(Other definitions for arctic that I've seen before include "Northernmost regions" , "Cold region in the northern hemisphere" , "icy conditions" , "Relating to northern polar regions" , "icy area" .)