Etymology: < (i) Anglo-Norman and Old French langor, langur, Anglo-Norman and Old French, Middle French langour, Old French languor, Old French, Middle French langueur, Middle French languer (French langueur ) disease, sickness, illness (early 12th cent.), emotional weariness or lowness of spirits caused by lovesickness (c1180), suffering (late 14th cent. or earlier), natural or affected lack of energy and alertness, often as an indication of a nonchalant or dispassionate nature (1580), expression or indication of such weariness or apathy in the voice, features, etc. (1670), (of a business activity) stagnation (1780), and its etymon (ii) classical Latin languor faintness, exhaustion, lassitude, weariness, sickness, illness, dimness, inactivity, idleness, inertness, apathy, feebleness < languēre (see languish v.) + -or -or suffix. Compare Old Occitan, Occitan langor (12th cent.), Catalan llangor (13th cent.), Spanish langor (a1400; rare after 18th cent.), Portuguese langor (15th cent.; also †languor), Italian languore (13th cent. as †langore), which all show a similar semantic range.Senses 1b and 4 were perhaps reinforced by association with long v.¹ and long adj.¹ respectively, both of which show Scots forms with medial -a- (compare forms at those entries). N.E.D. (1901) also gives the pronunciation (læ·ŋgwǫ̆ɹ) /ˈlæŋɡwə(r)/, noted by other dictionaries of the 19th and early 20th centuries, probably a spelling pronunciation.

Etymology: Partly < Anglo-Norman langurer and Middle French langorer, langourer, also (with change of conjugation) langorir to languish, to be languorous (12th cent. in Old French as languerer ; < langor , langour , langueur languor n.), and partly (especially in later use) < languor n. (compare forms at that entry). Compare earlier languish v. and slightly later languoring adj.