adj. & n.
adj. 1 of, concerned with, or essential to organic life (vital functions). 2 essential to the existence of a thing or to the matter in hand (a vital question; secrecy is vital). 3 full of life or activity. 4 affecting life. 5 fatal to life or to success etc. (a vital error). 6 disp. important.
n. (in pl.) the body's vital organs, e.g. the heart and brain. vital capacity the volume of air that can be expelled from the lungs after taking the deepest possible breath. vital force 1 (in Bergson's philosophy) life-force. 2 any mysterious vital principle. vital power the power to sustain life. vital statistics 1 the number of births, marriages, deaths, etc. 2 colloq. the measurements of a woman's bust, waist, and hips. vitally adv.
[ ME f. OF f. L vitalis f. vita life ]