n That which makes an act or an event unavoidable; irresistible force; overruling power; compulsion, physical or moral; fate; fatality.
n The negation of freedom in voluntary action; the subjection of all phenomena, whether material or spiritual, to inevitable causation; necessitarianism.
n (legal) Greater utilitarian good; used in justification of a criminal act.
n (legal|in the plural) Indispensable requirements (of life).