Definitions

life-threatening

[lahyf-thret-ning, -thret-n-ing] / ˈlaɪfˌθrɛt nɪŋ, -ˌθrɛt n ɪŋ /

ADJECTIVE

very dangerous

Synonyms

STRONGEST

deadly lethal mortal serious severe

WEAK

capital critical hazardous threatening touch and go unsafe

Antonyms

STRONGEST

harmless invigorating

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Eighteen percent reported that it led to a life-threatening event or required an intervention to prevent permanent harm.

From MarketWatch • Apr. 22, 2026

Two of the doctors failed to properly intervene as a pregnant teenager repeatedly sought care for life-threatening complications, the board found.

From Salon • Apr. 20, 2026

This is a life-threatening emergency that requires urgent hospital treatment.

From BBC • Apr. 18, 2026

A puppy is getting a new leash on life after being rescued with life-threatening facial injuries in Pasadena.

From Los Angeles Times • Apr. 7, 2026

Between the two of us, Bobby Gene and I had been in our share of fights around the playground, but nothing life-threatening.

From "The Season of Styx Malone" by Kekla Magoon