HARMFUL
harmful
(adjective) causing or capable of causing harm; “too much sun is harmful to the skin”; “harmful effects of smoking”
Source: WordNet® 3.1
Etymology
Adjective
harmful (comparative harmfuller or more harmful, superlative most harmful)
of a kind likely to be damaging; injurious
Usage notes
• 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.
Synonyms
• injurious; see also harmful
Antonyms
• beneficial
• harmless
Source: Wiktionary
Harm"ful, a.
Definition: Full of harm; injurious; hurtful; mischievous. " Most harmful
hazards." Strype. --Harm"ful*ly, adv.
– Harm"ful*ness, n.
Source: Webster’s Unabridged Dictionary 1913 Edition