1. Such as must be; impossible to be otherwise; not to be avoided; inevitable. Death, a necessary end, Will come when it will come. (Shak)
2. Impossible to be otherwise, or to be dispensed with, without preventing the attainment of a desired result; indispensable; requiste; essential. ‘T is necessary he should die. A certain kind of temper is necessary to the pleasure and quiet of our minds. (Tillotson)
3. Acting from necessity or compulsion; involuntary; opposed to free; as, whether man is a necessary or a free agent is a question much discussed.
Origin: L. Necessarius, from necesse unavoidable, necessary; of uncertain origin: cf. F. Necessaire.