One living abroad, formerly linked to French island (5)
I believe the answer is:
exile
'one living abroad' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'formerly linked to french island' is the wordplay.
'formerly' becomes 'ex' (prefix meaning former or onetime).
'linked to' means one lot of letters go next to another.
'french island' becomes 'ile' ('island' in French).
'ex'+'ile'='EXILE'
Can you help me to learn more?
(Other definitions for exile that I've seen before include "Person forced from country" , "Ban to abroad" , "forced to leave" , "Throw out" , "Ostracism" .)