Legal right to take a different line (4)
I believe the answer is:
lien
'legal right' is the definition.
(type of property right)
'a different line' is the wordplay.
'a different' indicates an anagram (letters placed in a different order).
'line' with letters rearranged gives 'LIEN'.
'to take' is the link.
(Other definitions for lien that I've seen before include "Legal claim on Nile" , "Security for a debt" , "Legal right over the Nile" , "Right to a lawyer" , "The right to take property if an obligation is not discharged" .)