Part of speech: Adjective (satellite)
not to be placated or appeased or moved by entreaty
Example: grim determination; grim necessity; Russia's final hour, it seemed, approached with inexorable certainty; relentless persecution; the stern demands of parenthood
un – A related word in the same word family.
appeasable – A related word in the same word family.
These related words all descended from the same ancestor thousands of years ago.