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

It’s commonly seen as too loud, too expensive, too unhealthy, too environmentally unfriendly, and an unnecessary eyesore that requires a lot of red tape between landlords and city permits to procure. — Morgan Simon, Forbes.com, 4 Aug. 2026

Wildfires in Washington and British Columbia, Canada, are also expected to bring hazy skies and unhealthy air quality to the state over the next two days as smoke moves in from the north and temperatures climb toward 100 degrees. — Amanda Jackson, CNN Money, 3 Aug. 2026

Wildfire smoke causing unhealthy conditions Much of the Northwest will remain under hazardous conditions this week, with gusty winds and high temperatures helping wildfires spread quickly. — Janet Loehrke, USA Today, 3 Aug. 2026

The air quality index was forecast to meet or exceed 126, a level that’s considered unhealthy for sensitive groups, including people with heart or lung disease, older adults, children and teenagers. — Haley Parsley august 1, Sacbee.com, 1 Aug. 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