unhealthy

adjective

un·​healthy ˌən-ˈhel-thē 

unhealthier; unhealthiest

1

: not conducive to health : not healthful

an unhealthy climate

unhealthy habits

unhealthy foods

2

: not in good health : sickly, diseased

unhealthy animals

3

a

: risky, unsound

an unhealthy economy

b

: of a harmful nature : bad, injurious

unhealthy eating habits

unhealthy levels of lead

c

: involving or causing feelings or thoughts that are not normal and healthy

an unhealthy relationship

has an unhealthy interest in natural disasters

unhealthily

ˌən-ˈhel-thə-lē 

adverb

unhealthiness

ˌən-ˈhel-thē-nəs 

noun

Synonyms of unhealthy

• poisonous
• toxic
• unhealthful
• unwholesome
• sickly
• noxious

Examples of unhealthy in a Sentence

Her skin looks blotchy and unhealthy.

Tests revealed an unhealthy level of lead in the water.

Eating honey can be unhealthy for babies.

He was stuck in an unhealthy relationship.

She has an unhealthy interest in natural disasters.

Recent Examples on the Web

Four of those five backs are attached to healthy offensive environments, and the fifth (Achane again) has demonstrated an ability to thrive in an unhealthy ecosystem. — Andy Behrens, New York Times, 21 July 2026

Conditions for the beginning of the work week are forecast at a minimum to be unhealthy for sensitive groups, which include people with heart or lung disease, older adults, teens and children. — Chicago Tribune, 20 July 2026

The alert signals that the air is unhealthy for sensitive groups, including children, older adults, and those with heart or lung disease. — Finch Walker, USA Today, 20 July 2026

Fine particle pollution is expected to reach the red category across all four regions under the alert, which means the air is unhealthy for everyone. — Kristi Miller, Twin Cities, 19 July 2026

Word History

First Known Use

1595, in the meaning defined at sense 1

Rhymes for unhealthy

• healthy
• stealthy
• wealthy

Kids Definition

unhealthy

adjective

un·​healthy ˌən-ˈhel-thē 

1

: not conducive to good health : not healthful

an unhealthy climate

2

: not in good health : sickly, diseased

3

a

: risky, unsound

an unhealthy economy

b

: injurious, bad

unhealthily

-thə-lē 

adverb

unhealthiness

-thē-nəs 

noun

Medical Definition

unhealthy

adjective

un·​healthy -ˈhel-thē 

unhealthier; unhealthiest

1

: not conducive to health

an unhealthy climate

2

: not in good health : sickly

unhealthiness noun