What does unhealthy mean?
Unhealthy is an adjective describing something that is harmful to health, not in good physical condition, or figuratively in a state of serious weakness or dysfunction. Its literal uses include describing food, habits, environments, and bodily conditions: an unhealthy diet may contribute to illness, while an unhealthy workplace may expose people to physical or psychological harm. The word also has a well-established figurative meaning. An economy, organization, relationship, or pattern of behavior can be called unhealthy when it is unstable, damaging, or likely to deteriorate. In these contexts, “unhealthy” suggests that a problem is more than a minor inconvenience and that corrective action may be needed. The word is widely understood in British and American English and is often more direct and forceful than alternatives such as “unsalubrious.” It belongs to the word family of health and healthy, using the prefix un- to negate the idea of good health.
adjectiveUnhealthy means harmful to health or not in a healthy condition. It can also describe something dangerous, unstable, dysfunctional, or otherwise in poor condition.
- Harmful to physical health; likely to impair or endanger health.
- Not healthy, sound, or well in physical condition.
- Figuratively unsafe, unstable, or harmful in its effects.
"The doctor advised him to change his unhealthy diet and begin exercising regularly."
"Poor ventilation and damp walls created an unhealthy environment in the old building."
"The report described the company's finances as unhealthy, with debt rising sharply."
One small prefix can turn a description into a warning: what is healthy can become unhealthy with the addition of un-.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does unhealthy come from?
Unhealthy was formed in English from health and the productive prefix un-, meaning “not” or “without.” The adjective developed with senses referring both to a condition that is not healthy and to something detrimental to health. It belongs to the same word family as health, healthy, healthful, and healthfully, which all share the English base health.
Related word forms
How unhealthy is actually used
Unhealthy is common in both formal and informal English. It can refer literally to health or figuratively to systems, economies, relationships, and habits that are functioning poorly.
Easily confused with unhealthy
Unhealthy is broader and can describe a person, condition, habit, environment, or figurative situation, whereas healthful is more formal and specifically means harmful to physical health.