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

Rabies is a viral disease that is nearly 100% fatal but is preventable when PEP is given appropriately before symptoms start, according to the CDC. — Joseph Hernandez, Kansas City Star, 24 Sep. 2026

Hayden Panettiere's fatal overdose is a stark reminder that the fentanyl crisis has not gone away, even as the United States makes genuine progress in reducing overdose deaths since peaking in 2022. — James Cirrone, FOXNews.com, 24 Sep. 2026

Carutasu was involved in another fatal shooting the following year, in which officers shot and killed 35-year-old Mario Sanchez after mistaking the cellphone in his hands for a firearm. — Libor Jany, Los Angeles Times, 24 Sep. 2026

These investigations require significant resources, but overdose deaths are often not prioritized by police in the same way as a fatal shooting. — Eric Levenson, CNN Money, 23 Sep. 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