Which word describes something that is offensive, disgusting, or harmful?

The word "noisome" specifically captures the essence of being offensive, disgusting, or harmful. It is often used to describe unpleasant smells, but it can also extend to things that are ethically or morally offensive. The origin of the word suggests an association with noxious qualities, which reinforces its connotation of harm or foulness.

In contrast, "innocuous" describes something that is harmless or safe, which directly opposes the notion of being offensive or disgusting. "Salutary" refers to something that is beneficial or health-promoting, again contrasting with the idea of harmfulness. The term "benign" describes something that is gentle or kindly, which does not align with the concept of being offensive or disgusting either.

Thus, "noisome" stands out as the most fitting choice for describing something that is offensive, disgusting, or harmful.