Foreigner deprived of a legal right (4)
I believe the answer is:
lien
'legal right' is the definition.
(I've seen this before)
'foreigner deprived of a' is the wordplay.
'foreigner' becomes 'alien' ('alien' can be a synonym of 'foreigner').
'deprived of' is a deletion indicator.
'alien' with 'a' removed is 'LIEN'.
(Other definitions for lien that I've seen before include "Legal claim on Nile" , "Right to another's property, if an obligation is not discharged" , "Right to retain property until a debt is paid" , "Sequestration order" , "The right to take property if an obligation is not met" .)