At least one of two fled from small country (8)
I believe the answer is:
andorran
'from small country' is the definition.
(Andorra is a small European country)
'at least one of two fled' is the wordplay.
'at least one of two' becomes 'and or' (and/or).
'fled' becomes 'ran' (ran away).
'andor'+'ran'='ANDORRAN'
(Other definitions for andorran that I've seen before include "Resident of microstate" , "Native to a principality in the Pyrenees" , "European" .)