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

The Environmental Protection Agency's (EPA) AirNow map, which provides a real-time snapshot of air quality, showed that air pollution levels around Sweet Home, northeast of Eugene, were in the unhealthy range on Friday morning. —Matthew Robinson, MSNBC Newsweek, 31 Oct. 2025

Although chocolate can sometimes be associated with unhealthy habits, like eating too much sugar, dark chocolate has many redeeming qualities. —Christina Manian, Health, 30 Oct. 2025

Dismissing, shaming, or escalating someone else’s feelings is a form of unhealthy co-regulation. —Marc Brackett, Time, 28 Oct. 2025

Sara Kuburic, a mental health professional known online as the millennial therapist, broke down the ins and outs of healthy (and unhealthy) soft-launching in a previous column for USA TODAY. —Charles Trepany, USA Today, 27 Oct. 2025

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