unavoidable casualty vs vis major

unavoidable casualty and vis major both are nouns.

Word	Noun	Adjective	Verb	Adverb
unavoidable casualty	Yes	No	No	No
vis major	Yes	No	No	No

As nouns, unavoidable casualty and vis major are synonyms defined as:

unavoidable casualty and vis major: a natural and unavoidable catastrophe that interrupts the expected course of events

Other synonyms of unavoidable casualty include act of God, force majeure, inevitable accident.

unavoidable casualty (noun)	vis major (noun)
a natural and unavoidable catastrophe that interrupts the expected course of events	a natural and unavoidable catastrophe that interrupts the expected course of events