late 15c., "austerity or strictness of life," from Middle French severite, from Latin severitas "seriousness, strictness, sternness," from severus "stern, strict, serious," of uncertain origin. Possibly from PIE root *segh- "to have, hold" (see scheme (n.)), or possibly from *se vero "without kindness," from se "without" (see secret) + *vero "kindness," neuter ablative of verus "true" (see very). Meaning "strictness in dealing with others" is recorded from 1520s.
