neurotoxin

This term is primarily used in scientific, medical, and biological contexts to describe substances that target the nervous system. It carries a clinical and precise tone, distinguishing it from the broader term "poison" or "toxin," which may affect any organ or system in the body.

In a practical sense, the word is often associated with specific biological sources, such as certain species of snakes, spiders, or bacteria. It describes a mechanism of action—specifically the disruption of nerve impulses—rather than just the general effect of illness or death.