Unhealthy means harmful to your body or mind, or not in a good condition for living things to thrive. When doctors warn against unhealthy foods, they mean foods that damage your body over time, like eating candy bars for every meal instead of getting balanced nutrition. An unhealthy plant has yellow, drooping leaves instead of green, vigorous growth.

The word applies beyond physical health. An unhealthy relationship might involve constant arguing, manipulation, or one person controlling another. An unhealthy obsession means caring about something so much that it crowds out other important parts of life, like a student so fixated on video games that friendships and schoolwork suffer.

Sometimes people use unhealthy to describe habits or patterns that cause problems. Staying up until 2 AM every night is an unhealthy sleep schedule. Constantly comparing yourself to others creates an unhealthy mindset. An unhealthy work environment might mean a place where people feel stressed, disrespected, or afraid.

The opposite of unhealthy is healthy. Notice that unhealthy doesn't always mean terrible or dangerous immediately. Some unhealthy choices cause problems slowly over time, which makes them easy to ignore until the damage adds up.