Synonyms for SEVERE : harsh, strict, tough, authoritarian, rigorous, stern, rigid, hard; Antonyms of SEVERE : gentle, mild, tolerant, lenient, easy, lax, indulgent ... Severe definition: harsh; unnecessarily extreme .. See examples of SEVERE used in a sentence. The adjective ' severe ' finds its etymological roots in the Latin word 'severus,' which conveyed the sense of being strict, stern, or serious. In Latin, 'severus' was used to describe individuals who displayed a strict or uncompromising demeanor. As the word transitioned into Middle English, it retained its core meaning of being intense, harsh, or extreme in nature. ' Severe ' is used to characterize situations, conditions, or judgments that are marked by a stern and uncompromising quality. It ... SEVERE meaning: 1. causing very great pain, difficulty, worry, damage, etc.; very serious: 2. extreme or very…. Learn more.