noun. The neutral bitter principle of quassia (Picræna excelsa).

noun. The bitter principle of quassia, extracted as a white crystalline substance; -- formerly called quassite.

noun. A very bitter triterpenoid lactone, extracted as white crystals from the quassia tree, used in traditional Chinese medicine

"He also carried a few leaves of quassin doe, the antidote for ten-step poison, but as the poison's name implied, haste with the quassin doe was essential."

quassinoid  

quassine  quassite  quassīin