the.com/toxicity

means The degree to which something is poisonous or harmful — how much damage it can do to a body, a mind, or a group of people.

from Traces back through Latin 'toxicum' (poison) to Greek 'toxikon,' which meant 'poison for arrows' — itself from 'toxon,' meaning bow. The lethal stuff coated the arrowhead before it ever entered the bloodstream of the language; 'toxic' didn't start out medical, it started out military.