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

Police have released body camera footage of a fatal police shooting on Wednesday. —Christa Swanson, CBS News, 13 Dec. 2025

The accident that takes Sonny out of the career in the first place was based on a real-life, near-fatal crash that occurred in 1990. —Alyssa Davis, PEOPLE, 12 Dec. 2025

The autoimmune disease, first described more than a decade after Austen died, occurs often in young women and can be fatal in their 30s and 40s. —Ashley Strickland, CNN Money, 12 Dec. 2025

There were high-profile legal scrapes, one for drug possession and a potentially fatal 2005 car accident on a road in Richmond’s Powhatan County. —Keith Murphy, VIBE.com, 12 Dec. 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