A legal right to be foreign (5)
I believe the answer is:
alien
'be foreign' is the definition.
(synonyms)
'a legal right' is the wordplay.
'legal right' becomes 'lien' (type of property right).
'a'+'lien'='ALIEN'
'to' acts as a link.
(Other definitions for alien that I've seen before include "Belonging to a foreign country" , "Someone from outer space?" , "Foreign; extraterrestrial" , "One is from outer space, perhaps" , "Foreign (from outer space?)" .)