Severe

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mid 16th century (in severe (sense 2)): from French sévère or Latin severus .

wiktionary

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From Middle French, from Latin severus(“severe, serious, grave in demeanor”).

etymonline

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severe (adj.)

1540s, from French severe (12c., Modern French sévère) or directly from Latin severus "serious, grave, strict, austere," which is probably from PIE root *segh- "to have, hold," on the notion of "steadfastness, toughness." From 1660s with reference to styles or tastes; from 1725 of diseases.