1. [ adjective ] not causing or capable of causing harm

"harmless bacteria" "rendered the bomb harmless"

Related terms: harmful innocent inoffensive safe painless innocuous nontoxic benign
2. [ adjective ] unlikely to harm or disturb anyone
Synonyms: innocuous

"harmless old man"

Related terms: safe
3. [ adjective ] not injurious to physical or mental health
Synonyms: innocuous
Related terms: noxious inoffensive insipid innoxious
4. [ adjective ] not producing any toxic effects
Related terms: nontoxic
5. [ adjective ] (pathology) not threatening to life or health; not malignant
Synonyms: nonmalignant

"a benign tumor is usually harmless"

Related terms: pathology benign
Similar spelling:   harmlessly