IPA: /ˌɪnəˈpiːzəbl/
KK: /ɪnəˈpiːzəbl/
Something that cannot be satisfied or calmed down, often referring to strong feelings or demands.
His inappeasable anger made it hard for anyone to reason with him.
Inappeasable → It is formed from "in-" (meaning not), "appeasable" (from the verb "appease" which comes from Old French *apaisier*, meaning to calm or pacify, and the suffix "-able" meaning capable of). The word describes something that cannot be calmed or pacified.
Think of 'not' ('in-') being able to 'calm' ('appeasable') — that's why inappeasable means something that cannot be calmed.