force majeure vs unavoidable casualty

force majeure and unavoidable casualty both are nouns.

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

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

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

Other synonyms of force majeure include act of God, inevitable accident, vis major.

force majeure (noun)	unavoidable casualty (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