Northerner's one night abroad (5)
I believe the answer is:
inuit
'northerner's' is the definition.
(I've seen this before)
'one night abroad' is the wordplay.
'one' becomes 'i' (Roman numeral).
'night abroad' becomes 'nuit' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'i'+'nuit'='INUIT'
Can you help me to learn more?
(Other definitions for inuit that I've seen before include "northern folk" , "People inhabiting the Arctic" , "Indigenous Greenlander" , "Lifetime's occupation" , "One from the far north" .)