poisonous plant (also known as monkshood and wolfsbane), 1570s, from French aconit (16c.), from Latin aconitum, from Greek akoniton, which is of unknown origin.
The highly poisonous alkaloid in it, once isolated, was named aconitine (1826). The ancient folk-etymology of the name is Derived by the ancients from Greek akoniti "without dust," hence "without struggle or fight," hence "invincible" in its deadly effect. But Beekes finds this "hardly possible" and proposes a substrate origin.