A chemical that causes you to become sick is an example of a chemical that would be described as harmful.
(comparative harmfuller or more harmful, superlative harmfullest or most harmful)
- Nouns to which "harmful" is often applied: effect, consequence, impact, influence, emission, chemical, ingredient, substance, gas, agent, additive, drug, radiation, dust, organism, plant, animal, insect, action, act, behavior, component, content, activity, interference, use.
From harm + -ful.
- The Egyptian rule proved harmful to the country.
- The ordinary pleasures of life were for them not merely negligible but positively harmful inasmuch as they interrupted the operation of the will.
- Though harmful to the economic condition of the island, it left agriculture comparatively unaffected, because the insolvent institutions had never fulfilled the objects of their foundation.
- Spiritualism has been accused of a tendency to produce insanity, but spiritualistic sittings carried on by private persons do not appear to he harmful provided those who find in themselves "mediumistic" powers do not lose their self-control and exercise these powers when they do not desire to do so, or against their better judgment.
- An institution upholding honor, the source of emulation, is one similar to the Legion d'honneur of the great Emperor Napoleon, not harmful but helpful to the success of the service, but not a class or court privilege.