Force majeure

(French) superior force, event that cannot be controlled or anticipated

Force majeure (French for "greater force") is a common clause in contracts which essentially frees one or both parties from liability or obligation when an extraordinary event or circumstance beyond the control of the parties, such as war, strike, riot, crime, act of God (e.g., flooding, earthquake, volcano), prevents one or both parties from fulfilling their obligations under the contract. However, Force Majeure is not intended to excuse negligence or other malfeasance of a party, as where non-performance is caused by the usual and natural consequences of external forces (e.g., predicted rain stops an outdoor event), or where the intervening circumstances are specifically contemplated.
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Noun
1. a natural and unavoidable catastrophe that interrupts the expected course of events; "he discovered that his house was not insured against acts of God"
(synonym) act of God, vis major, inevitable accident, unavoidable casualty
(hypernym) calamity, catastrophe, disaster, tragedy, cataclysm

n. circumstances outside one's control

n. act of God