Foreigner having a legal right (5)
I believe the answer is:
alien
'foreigner' is the definition.
(synonyms)
'a legal right' is the wordplay.
'legal right' becomes 'lien' (I've seen this before).
'a'+'lien'='ALIEN'
'having' acts as a link.
(Other definitions for alien that I've seen before include "Foreigner, outsider" , "Foreign - film directed by Ridley Scott" , "coming from overseas" , "ET" , "Foreign; extraterrestrial" .)