Freezing cold in lorry (6)
I believe the answer is:
arctic
'freezing' is the definition.
(synonyms)
'cold in lorry' is the wordplay.
'cold' becomes 'C' (eg on taps).
'in' is an insertion indicator.
'lorry' becomes 'artic' (articulated lorry is a semi-trailer truck).
'c' placed into 'artic' is 'ARCTIC'.
(Other definitions for arctic that I've seen before include "It's cold at the top" , "Relating to northern polar regions" , "Relating to the North Pole area" , "Relating to North Pole region" , "Area around the North Pole" .)