concessor
/ˈkɑnsɛsər/Definitions
1. noun
A person or thing that concedes or grants something, especially a privilege or a right.
“The government appointed the negotiator as a key concessor in the peace talks.”
2. noun
A person or thing that admits defeat or gives up a claim or advantage.
“The company’s new policy made it difficult for the concessor to continue the lawsuit.”