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.

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

The disorder causes constant, relentless hunger through hypothalamic dysfunction, where the brain fails to register fullness, often leading to life-threatening obesity.

From Barron's • Apr. 6, 2026

Such reactions can range from responses with “no clinical manifestations” to irritating rashes to life-threatening conditions such as anaphylactic shock, which constricts breathing and impairs motor function.

From Salon • Apr. 4, 2026

Ectopic pregnancies are when the embryo starts growing outside the womb, usually in the fallopian tube, and can be life-threatening.

From BBC • Mar. 9, 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