Immigrant needs a legal right (5)
I believe the answer is:
alien
'immigrant' is the definition.
(thesaurus)
'a legal right' is the wordplay.
'legal right' becomes 'lien' (I've seen this before).
'a'+'lien'='ALIEN'
'needs' is the link.
(Other definitions for alien that I've seen before include "movie!" , "Foreign (from outer space?)" , "Belonging to a foreign country" , "immigrant" , "Foreign - film directed by Ridley Scott" .)