Reduce agreement (8)
I believe the answer is:
contract
I believe this is a double definition.
'reduce' is the first definition.
(synonyms)
'agreement' is the second definition.
(contract is a kind of agreement)
(Other definitions for contract that I've seen before include "Document setting out terms of agreement" , "Covenant" , "Agree - get smaller" , "Agree - reduce" , "four spades, perhaps" .)