fatal

adjective

fa·​tal ˈfā-tᵊl 

1

a

: causing death

a fatal crash

a fatal disease

a fatal wound

b

: bringing ruin

a fatal attraction to gambling

c

: causing failure

a fatal design flaw

Lack of sufficient support was fatal to his campaign.

2

a

: determining one's fate

the fatal flaw in this dazzling woman: a total lack of taste

—Marya Mannes

b

: of or relating to fate

… this science sets a fatal necessity on things …

—H. O. Taylor

c

: resembling fate in proceeding according to a fixed sequence

3

: fateful

a fatal hour

4

obsolete : fated

Synonyms

• disastrous
• catastrophic
• unfortunate

Choose the Right Synonym for fatal

deadly, mortal, fatal, lethal mean causing or capable of causing death.

deadly applies to an established or very likely cause of death.

a deadly disease

mortal implies that death has occurred or is inevitable.

a mortal wound

fatal stresses the inevitability of what has in fact resulted in death or destruction.

fatal consequences

lethal applies to something that is bound to cause death or exists for the destruction of life.

lethal gas

Examples of fatal in a Sentence

a disease that is often fatal

a chemical that can be fatal to birds

She made a fatal mistake.

Recent Examples on the Web

An attack in Boulder, Colorado, in June and the fatal shooting of two Israeli embassy employees in Washington, D.C., in May, are two recent incidents of anti-Jewish violence that have rocked communities in the U.S. Advertisement Read More: The Rise of Antisemitism and Political Violence in the U.S. —Rebecca Schneid, Time, 5 July 2025

Most had gone to sleep by the time of the fatal brawl. —Emma Seiwell, New York Daily News, 5 July 2025

What wasn’t reported was Rivera’s aversion to pitches coming near him, a trait that’s fatal to long-term hitting success. —Tom Krasovic, San Diego Union-Tribune, 4 July 2025

Two people have been charged in connection with the fatal June 16 shooting of Remoin Thomas Patton Sr. —Christina Coulter, People.com, 4 July 2025

Word History

Etymology

Middle English, from Latin fatalis, from fatum fate

First Known Use

14th century, in the meaning defined at sense 4

Phrases Containing fatal

• dealt a fatal blow

Rhymes for fatal

• datal
• antenatal
• neonatal
• perinatal
• hiatal
• nonfatal
• postnatal
• prenatal

Kids Definition

fatal

adjective

fa·​tal ˈfāt-ᵊl 

1

: deciding one's fate : fateful

on that fatal day

2

: causing death or ruin

a fatal accident

fatally

-ᵊl-ē

adverb

Medical Definition

fatal

adjective

fa·​tal ˈfāt-ᵊl 

: causing death

a fatal diabetic coma

—Havelock Ellis

fatally

ˈfāt-ᵊl-ē 

adverb

Legal Definition

fatal

adjective

fa·​tal

1

: causing failure of a legal claim or cause of action

a fatal defect in the proceedings

—W. R. LaFave and J. H. Israel

2

: making something (as a contract) invalid or unenforceable

there is a fatal indefiniteness with the result that the agreement is void

—J. D. Calamari and J. M. Perillo

fatally adverb