late 15c. (Caxton), "austerity or strictness of life," from French severite, from Latin severitatem (nominative severitas) "seriousness, strictness, sternness," a derivative of severus "stern, strict, serious" (see severe). The meaning "strictness in dealing with others" is recorded from 1520s. OED marks severeness (1570s) as "rare."
updated on July 07, 2022