unavoidable casualty vs force majeure

unavoidable casualty and force majeure both are nouns.

Word	Noun	Adjective	Verb	Adverb
unavoidable casualty	Yes	No	No	No
force majeure	Yes	No	No	No

As nouns, unavoidable casualty and force majeure are synonyms defined as:

unavoidable casualty and force majeure: a natural and unavoidable catastrophe that interrupts the expected course of events

Other synonyms of unavoidable casualty include act of God, inevitable accident, vis major.

unavoidable casualty (noun)	force majeure (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