Lender's security (4)
I believe the answer is:
lien
'lender's security' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for lien that I've seen before include "Right to another's property, if an obligation is not discharged" , "Right to keep property" , "Right to a lawyer" , "Legal right to detain property" , "The right to take property if an obligation is not discharged" .)