Arctic city bordered by two rivers (5)
I believe the answer is:
polar
'arctic' is the definition.
(I know that arctic can be written as polar)
'bordered by two rivers' is the wordplay.
'two rivers' can mean two replacements for 'river'.
'bordered' becomes 'la' (I can't justify this - if you can you should give a lot more credence to this answer).
'by' says to put letters next to each other.
'river' becomes 'Po' (Italian river).
'river' becomes 'r' (abbreviation for river).
'la' put after 'po' is 'pola'.
'pola'+'r'='POLAR'
'city' is the link.
I am not very happy about this link. It may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for polar that I've seen before include "- bear; - cap" , "Arctic and Antarctic regions, for example" , "Of the cold regions" , "Of the highest latitude" , "Relating to Earth's coldest regions" .)