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

Simmons said very few improvements have been made to the highway, even as the fatal accidents continue to happen. —Julie Gallant, San Diego Union-Tribune, 29 July 2025

The 2024 case was not fatal, health department spokesperson Kimberly Harry indicated on July 28. —Christina Hall, Freep.com, 29 July 2025

Plants tolerate brief periods of drought, but wet soils can be fatal, especially during dormancy. —Kim Toscano, Southern Living, 28 July 2025

Six victims in total sustained gunshot wounds, with three being fatal. —Tristan Maglunog, ABC News, 28 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