Arctic jacket (6)
I believe the answer is:
anorak
'arctic jacket' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for anorak that I've seen before include "Socially inept person" , "Garment; studious person" , "Jacket; nerd (colloq.)" , "Zipped jacket with hood attached" , "Coat - nerd" .)