French. A superior force. A force which cannot be resisted. In other words, something beyond the control of the parties involved and which cannot be controlled. An event that cannot be reasonably anticipated. Includes Acts of God (see which) and acts of man (riots, strikes, arson, etc.). vis Major. Used primarily in insurance but may be extended to any type of performance contract, such as construction. A clause in a contract that denotes an act or an event that is beyond the control or power of the parties to control or prevent but when such an act happens performance will be excused.