strychnine

noun

1. (uncountable, usually)A very toxic, colorless crystalline alkaloid, derived from nux vomica, used as a pesticide.

   “Only don’t say I didn’t warn you if he burns Green Gables down or puts strychnine in the well—I heard of a case over in New Brunswick where an orphan asylum child did that and the whole family died in fearful agonies.”

   “[…] strychnine is a fairly rapid drug in its action. The symptoms appear from one to two hours after it has been swallowed.”