curare (n.)

formerly also curari, curara, resinous plant substance used by South American natives for poisoning their arrows, later used medicinally as a muscle relaxant, 1777, from Portuguese or Spanish curare, a corruption of the name in the Carib language of the Macusi Indians of Guyana, wurali or wurari, which had a sort of click sound at the beginning, and is said to mean "he to whom it comes falls" (when introduced into the blood the effect is almost instantly fatal).