IPA: /ˌʌnəˈpiːzəbl/
KK: /ʌnəˈpiːzəbl/
Something that cannot be satisfied or calmed down, often referring to strong feelings or desires.
His unappeasable anger made it difficult for anyone to reason with him.
Unappeasable → It is formed from "un-" (meaning not), "appease" (from Old French *apaisier*, meaning to calm or pacify), and "-able" (meaning capable of). The word "unappeasable" means not capable of being calmed or pacified.
Think of 'not' ('un-') being able to 'calm' ('appease') someone — that's why unappeasable means someone who cannot be calmed.