serpentine (n.) Look up serpentine at Dictionary.com
c.1400, "plant reputed to contain antivenom," from O.Fr. serpentin (fem. serpentine), from L.L. serpentius "of a serpent," from L. serpentem (nom. serpens) "snake" (see serpent). As the name of a greenish mineral, attested from early 15c. The adj. meaning "twisting, winding" first recorded 1610s (an earlier adj. meaning "having the evil qualities of a serpent" is recorded from late 14c.). The winding lake of that name in Hyde Park, London, was constructed in 1730.