life-threatening

adjective

life-threat·​en·​ing ˈlīf-ˌthre-tᵊn-iŋ 

-ˌthret-niŋ

: capable of causing death : potentially fatal

a life-threatening disease/condition

The injuries are serious but not life-threatening.

Examples of life-threatening in a Sentence

Recent Examples on the Web

The hurricane center warned that Polo's deluge could cause life-threatening flooding and mudslides, in particular in Guerrero. — Megan Janetsky, Arkansas Online, 24 Sep. 2026

New Mexico is preparing for another day of possibly life-threatening floods throughout most of the state after receiving multiple rounds of heavy monsoon rain since Tuesday. — Megan Fahrney, ABC News, 23 Sep. 2026

When withdrawal poses a risk Another potential risk during rehab is withdrawal itself, which can range from uncomfortable to life-threatening depending on the substance involved and the person’s level of physical dependence, according to Kardaris. — Melissa Rudy, FOXNews.com, 22 Sep. 2026

Though the storm is expected to remain offshore, the area could see life-threatening flooding and mudslides, particularly in steep terrain. — Iris Kwok, Los Angeles Times, 22 Sep. 2026

Word History

First Known Use

1759, in the meaning defined above

Medical Definition

life-threatening

adjective

life-threat·​en·​ing ˈlīf-ˌthret-ən-iŋ 

: capable of causing death : potentially fatal

life-threatening injuries

a life-threatening allergic reaction

life-threatening arrhythmia