Of the Arctic or Antarctic (5)
I believe the answer is:
polar
This clue is a double definition.
'of the arctic' is the first definition.
(I've seen this in another clue)
'antarctic' is the second definition.
(similar in meaning)
(Other definitions for polar that I've seen before include "- bear; - cap" , "From one end of the Earth or the other" , "Of the highest latitude" , "Having opposite extremes" , "having magnetic attraction" .)