Synonyms of the word

life-threatening

• adj. Endangering the continued life of the subject.

critical

• adj. Inclined to find fault or criticize; fastidious; captious; censorious; exacting.
• adj. Pertaining to, or indicating, a crisis or turning point.
• adj. Extremely important.
• adj. Relating to criticism or careful analysis, such as literary or film criticism.
• adj. (medicine) Of a patient condition involving unstable vital signs and a prognosis that predicts the condition…
• adj. Likely to go out of control if disturbed, that is, opposite of stable.
• adj. Of the point (in temperature, reagent concentration etc.) where a nuclear or chemical reaction becomes…
• n. A critical value, factor, etc.
• n. In breakdancing, a kind of airflare move in which the dancer hops from one hand to the other.

dangerous

• adj. Full of danger.
• adj. Causing danger; ready to do harm or injury.
• adj. (colloquial, dated) In a condition of danger, as from illness; threatened with death.
• adj. (obsolete) Hard to suit; difficult to please.
• adj. (obsolete) Reserved; not affable.

grave

• n. An excavation in the earth as a place of burial.
• n. Any place of interment; a tomb; a sepulcher.
• n. death, destruction.
• v. (transitive, obsolete) To dig.
• v. (transitive, obsolete) To carve or cut, as letters or figures, on some hard substance; to engrave.
• v. (transitive, obsolete) To carve out or give shape to, by cutting with a chisel; to sculpture.
• v. (transitive, obsolete) To impress deeply (on the mind); to fix indelibly.
• v. (transitive, obsolete) To entomb; to bury.
• v. (transitive, obsolete, nautical) To clean, as a vessel's bottom, of barnacles, grass, etc., and pay it…
• v. (intransitive, obsolete) To write or delineate on hard substances, by means of incised lines; to practice…
• adj. (obsolete) Influential, important; authoritative.
• adj. Characterised by a dignified sense of seriousness; not cheerful, sombre.
• adj. Low in pitch, tone etc.
• adj. Serious, in a negative sense; important, formidable.
• n. A written accent used in French, Italian, and other languages. è is an e with a grave accent.

grievous

• adj. Causing grief, pain or sorrow.
• adj. Serious, grave, dire or dangerous.

serious

• adj. Without humor or expression of happiness; grave in manner or disposition; earnest; solemn.
• adj. Important; weighty; not insignificant.
• adj. Really intending what is said; in earnest; not jocular or deceiving.

severe

• adj. Very bad or intense.
• adj. Strict or harsh.
• adj. Sober, plain in appearance, austere.