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 …

—Henry Osborn Taylor

c

: resembling fate in proceeding according to a fixed sequence

3

: fateful

a fatal hour

4

obsolete : fated

Synonyms of fatal

• 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

Legal experts cast doubt Monday on Bryan Kohberger’s petition to withdraw his guilty plea in the fatal stabbings of four University of Idaho students in 2022. — Emanuella Grinberg, NBC news, 28 July 2026

Tasmanian devils suffer from Devil Facial Tumor Disease (DFTD), a highly fatal cancer spread by biting, which has devastated their population and surprisingly arose twice. — John Drake, Forbes.com, 27 July 2026

In the aftermath of the fatal shooting, Baldwin faced a felony involuntary manslaughter count that was dismissed at trial. — Charisma Madarang, Rolling Stone, 27 July 2026

The fatal attack follows another homicide in the upscale seaside city. — Libor Jany, Los Angeles Times, 27 July 2026

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
• hiatal
• neonatal
• perinatal
• 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