Poisonous, definitely poisonous. That is, I’d much rather encounter a poisonous animal than a venomous one. Why? Let me explain…
Contrary to how they’re often used, the words venomous and poisonous (and by extension venom and poison) are not interchangeable. They’re similar of course, and venom and poison are basically the same thing, but there is a key difference.
A venomous animal is one that deliberately injects venom into a victim, through fangs, a stinger, or some other delivery method. A poisonous animal is one that contains a harmful substance, but does not deliberately inject that substance. You might be harmed by a poisonous animal by eating it, touching it, rubbing it all over your face, or whatever else you want to do with it. But at least it’s not going to try to inject venom into you. And that’s why I’d rather come across a poisonous animal: if I leave it alone, it’s probably not going to actively try to kill me.
But if you do run afoul of a venomous animal, what should you do? Seek out medical attention of course, and try to get hold of some antivenin.
Wait, what? Don’t I mean antivenom? I do, because antivenom and antivenin are the same thing. Antivenin comes from the French venin (venom) and was in quite common use in English for most of the 20th century. It was only in 1981 that the WHO officially declared that antivenom should be the preferred term in English, to avoid confusion. And probably because most English speakers had already been saying antivenom anyway, because antivenin in English sounds basically the same, and it’s a lot more logical than antivenin. At least it was probably never as confusing as flammable and inflammable. I can’t imagine running into a hospital anywhere in the world, screaming desperately for antivenom, and being met with blank stares, or even worse, smug grins as the staff waited for you to use the correct term.
Still, there are pedants all over the world, and people who like to stick to outmoded terms. So if you’re planning on trekking through remote jungles any time soon, be prepared to scream in semi-conscious agony for antivenom or antivenin, just in case.
UPDATE: In perhaps a venomous twist on the Baader-Meinhof phenomenon, a few hours after writing this post I was stung by a wasp, in retaliation for leaning back against him, unaware as I was that we see sharing the seat. Maybe I was tempting fate by writing this article, and I should postpone that one about the words deadly and lethal…