accidental

adjective

ac·​ci·​den·​tal ˌak-sə-ˈden-tᵊl 

1

a

: occurring unexpectedly or by chance

an accidental discovery

Their meeting was purely accidental.

b

: happening without intent or through carelessness and often with unfortunate results

The death was ruled accidental.

2

: arising from extrinsic causes : incidental, nonessential

3

of a bird : appearing outside its normal geographic range, migration route, or season

accidentalness

ˌak-sə-ˈden-tᵊl-nəs 

noun

Frequently Asked Questions

What is the difference between accidental and incidental?

Accidental describes what was not planned or intended. It means "happening by accident" or "happening as an accident," as in "an accidental discovery" and "an accidental injury." Incidental typically means "happening as a minor part or result of something else," as in "a chapter that is incidental to the novel's plot." For more information read the full article.

Do you say 'on accident' or 'by accident'?

While both "by accident" and "on accident" are used, "by accident" is far more common.

What does 'accident waiting to happen' mean?

The phrase "an accident waiting to happen" refers to a person or thing that is dangerous or unsafe. For example, a very clumsy person and a rickety ladder might both be referred to as "an accident waiting to happen."

Synonyms of accidental

• chance
• inadvertent
• unexpected
• unintentional
• incidental
• casual
• unintended
• unplanned
• fortuitous

Choose the Right Synonym for accidental

accidental, fortuitous, casual, contingent mean not amenable to planning or prediction.

accidental stresses chance.

any resemblance to actual persons is entirely accidental

fortuitous so strongly suggests chance that it often connotes entire absence of cause.

a series of fortuitous events

casual stresses lack of real or apparent premeditation or intent.

a casual encounter with a stranger

contingent suggests possibility of happening but stresses uncertainty and dependence on other future events for existence or occurrence.

the contingent effects of the proposed law

Examples of accidental in a Sentence

an accidental discovery of oil

The timing of the announcement was purely accidental.

The death was ruled accidental.

Recent Examples on the Web

In 2023, her 17-year-old son, Elijah, was killed in an accidental shooting. —Veronica Ortega, CBS News, 6 June 2026

Because this material was found at such profound layers, researchers had to hypothesize that accidental burning would have been impossible. —Maria Mocerino, Interesting Engineering, 6 June 2026

So to stage an accidental crash, the men swim down and move Ashe's body to the front seat of the car. —Emily Blackwood, PEOPLE, 5 June 2026

Environmental exposure was considered a contributing factor, and the manner of death was ruled accidental. —Jeff McDonald, San Diego Union-Tribune, 4 June 2026

Word History

Etymology

Middle English, borrowed from Anglo-French accidentel, borrowed from Late Latin accidentālis, from Latin accident-, accidens accident + -ālis -al entry 1

First Known Use

14th century, in the meaning defined at sense 2

Rhymes for accidental

• compartmental
• continental
• detrimental
• elemental
• fundamental
• governmental
• incidental
• incremental
• instrumental
• interdental
• monumental
• nonjudgmental

Kids Definition

accidental

1 of 2 adjective

ac·​ci·​den·​tal ˌak-sə-ˈdent-ᵊl 

1

: happening unexpectedly or by chance

an accidental discovery of oil

2

: not happening or done on purpose

an accidental fall

accidentally

-ˈdent-lē 

-ˈdent-ᵊl-ē

adverb

accidental

2 of 2 noun

: a musical note whose pitch is changed (as by a sharp or a flat) from the pitch shown in the key signature