Get smaller legal document (8)
I believe the answer is:
contract
I believe this is a double definition.
'get smaller' is the first definition.
(I've seen this before)
'legal document' is the second definition.
(contract is a kind of legal document)
(Other definitions for contract that I've seen before include "Become smaller" , "Agree - get smaller" , "Agreement - lessen" , "Make smaller" , "Promise" .)