Latin word inevitabilis comes from Latin evitabilis (Avoidable.), Latin ingratus (Thankless. Ungrateful. Unpleasant, disagreeable.)

Detailed word origin of inevitabilis

Dictionary entry	Language	Definition
evitabilis	Latin (lat)	Avoidable.
ingratus	Latin (lat)	Thankless. Ungrateful. Unpleasant, disagreeable.
inevitabilis	Latin (lat)	Unavoidable.