"Unhealthy" 是一个形容词，指的是不健康的。它来源于英语中的 "un-" 和 "healthy"，"un-" 是否定前缀，"healthy" 指健康的。
例句：
Eating too much junk food can lead to an unhealthy diet. (吃太多垃圾食品可能导致不健康的饮食)
Sitting in front of a computer for long hours is considered unhealthy. (长时间坐在电脑前被认为是不健康的)
Unhealthy habits such as smoking and excessive drinking can greatly increase the risk of disease. (不健康的习惯，如吸烟和过度饮酒，可能会大大增加患病的风险)