noxious
1. [ adjective ] injurious to physical or mental health
Synonyms: harmful
Examples:

"noxious chemical wastes" "noxious ideas"

Related terms: innocuous baneful vesicatory corrupting toxic unwholesome harmful
2. [ adjective ] harmful to living things
Synonyms: hurtful injurious deleterious
Examples:

"deleterious chemical additives"

Related terms: harmful