luxus.

Perhaps from Proto-Italic *luksos, from Proto-Indo-European *lug-sό-s, from Proto-Indo-European *léwg-os ~ *léwg-es-os (“bend, twist”), from *lewg- (“to bend”), whence also luctor (“to wrestle”). If this theory is accepted, then the term is cognate with Sanskrit rugṇá (“bent, broken”), Ancient Greek λύγος (lúgos, “twig, withe”), Lithuanian lugnas, and Old Norse lykna (“to bend, close”).

Disputed. *The rare sense 'dislocation' is presumably an abstract u-stem noun (see -tus) formed on the same stem as the adjective luxus (see above). *The more common sense 'luxury, extravagance' may be a metaphorical extension from "bending" to "lack of restraint". Alternatively, it may have a separate etymology from Proto-Indo-European *dluk-s-u-, a u-stem adjective built to *dluk-s-ό (“sweet”), itself perhaps from *dléwk-es- (“sweetness”), whence perhaps Ancient Greek γλεῦκος (gleûkos, “sweet wine”). However, the etymology of the Greek term is highly contentious, and it may derive from a non-IE substrate. For a semantic association between "sweetness" and "luxury," compare Italian dolce vita.