Meaning

adjective drooping without elasticity; wanting in stiffness

adjective out of condition; not strong or robust; incapable of exertion or endurance

originEtymology tree Latin flaccus Proto-Indo-European *-éh₁ti Proto-Indo-European *-yeti Proto-Indo-European *-éh₁yeti Proto-Italic *-ēō Latin -eō Latin flacceō Proto-Indo-European *dʰeh₁-der. Proto-Italic *-iðos Latin -idus Latin flaccid(us)bor. English flaccid Borrowed from Latin flaccid(us).

Etymology from Wiktionary, CC BY-SA 3.0