late 15c., "austerity or strictness of life," from M.Fr. severite, from L. severitas, from severus "stern, strict, serious," 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.