有害 (yǒu hài) means 'harmful' and is used as a predicate, often with 对 (duì) to indicate what is harmed. It emphasizes causing actual damage or toxicity, stronger than 不良 (bù liáng 'bad, unhealthy') which describes negative qualities, and different from 不利 (bù lì 'unfavorable') which focuses on disadvantageous conditions.