the quality or state of being necessary, unavoidable, or absolutely requisite; inevitableness; indispensableness.-the condition of being needy or necessitous; pressing need; indigence; want.-that which is necessary; a necessary; a requisite; something indispensable; -- often in the plural.-that which makes an act or an event unavoidable; irresistible force; overruling power; compulsion, physical or moral; fate; fatality.-the negation of freedom in voluntary action; the subjection of all phenomena, whether material or spiritual, to inevitable causation; necessitarianism.