The verb placate means to say or do something to make someone stop feeling angry.
Synonyms are appease, pacify, mollify, or soothe.
The word origins from 1670s. It is a back formation of Latin placation or else from Latin placatus meaning “soothed, quiet, gentle, calm, peaceful”, past participle of placare meaning “to calm, appease, quiet, soothe, assuage”, causative of placere meaning “to please”.
She knows he just wants to placate her but she doesn’t need it.
I think nothing I could say would placate him.
His mother did everything to placate him.