What is Unhealthy ?
Unhealthy is adj 1. not healthy I thought her face was an unhealthy colour. 2. which does not make you healthy The of- fice is very unhealthy, and most of the staff seem to be ill all the time. Sitting around smoking and not doing any sport is very un- healthy. Their children have a very un- healthy diet. 3. unnatural She has an unhealthy interest in dead bodies. (NOTE: un- healthier – unhealthiest)
source: Easier English, Student Dictionary Upper Intermediate Level