Literally, French for "greater force" and in older contracts, an "act of God"- an event beyond human control, such as weather, hurricanes, earthquakes, etc. In insurance and travel contracts, this is the "weasel phrase" meaning "shit happens", or at greater length, "it's out of our hands, so we don't have to do anything for you" - if your flight is cancelled because of weather, it is considered to be cancelled because of force majeure and in most cases you are SOL for lodging, meals etc. until they can arrange to get you out on another flight, perhaps days later.
From one airline's "Conditions of Carriage":

FORCE MAJEURE EVENTS
American (Airlines) may, in the event of a force majeure event, without notice, cancel, terminate, divert, postpone or delay any flight or the right of carriage or reservation of traffic accommodations without liability except to issue an involuntary refund. The involuntary refund will be made in the original form of payment in accordance with involuntary refund rules for any unused portion of the ticket. American will also reserve the right to determine if any departure or landing should be made without any liability except the afore mentioned involuntary refund.

Force Majeure Event Means:

Any condition beyond American's control including, but without limitation, meteorological conditions, acts of God, riots, civil commotion, embargoes, wars, hostilities, disturbances or unsettled international conditions - actual threatened or reported. Also, because of any delay, demand, circumstances or requirement due, directly or indirectly to such conditions, or
Any strike, work stoppage, slowdown, lockout or any other labor related dispute involving or affecting American's service, or
Any government regulation, demand or requirement, or
Any shortage of labor, fuel or facilities of American or others, or
Any fact not reasonably foreseen, anticipated or predicted by American.
by JDiver June 6, 2010
Get the force majeure mug.
The sexual position that involves having intercourse during a catastrophic event such as an earthquake, hurricane, tornado or wildfire.
We totally did it force majeure while watching Hurricane Sandy on the weather channel. It was hot.
by mos fet January 29, 2013
Get the force majeure mug.
When a guy cums before a girl, therefore ruining the sexytime
Terry, really, you force majeured again last night? Your girl is gonna leave you
by Namistrone May 10, 2021
Get the Force Majeure mug.