Pact or agreement (6)
I believe the answer is:
treaty
This clue is a double definition.
'pact' is the first definition.
(I know that pact can be written as treaty)
'agreement' is the second definition.
(I know that agreement can be written as treaty)
(Other definitions for treaty that I've seen before include "Formal agreement between governments" , "convention?" , "settlement" , "A pact between countries" , "Political or private agreement" .)