swear

American  

[swair] / swɛər /

verb (used without object)

swore, sware, sworn, swearing

1. to make a solemn declaration or affirmation by some sacred being or object, as a deity or the Bible.

   Synonyms:

   avow, affirm, declare

2. to bind oneself by oath.

3. to give evidence or make a statement on oath.

   Synonyms:

   testify, depose

4. to use profane oaths or language.

   Don't swear in front of the children.

   Synonyms:

   imprecate

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verb (used with object)

swore, sware, sworn, swearing

1. to declare, affirm, attest, etc., by swearing by a deity, some sacred object, etc.

2. to affirm, assert, or say with solemn earnestness.

3. to promise or undertake on oath or in a solemn manner; vow.

4. to testify or state on oath.

   He swore it on the witness stand.

5. to take (an oath), as in order to give solemnity or force to a declaration, promise, etc.

6. to bind by an oath.

   to swear someone to secrecy.

noun

1. Informal. a profane or obscene word; curse word.

   If we said a swear, Mom made us put a quarter in the jar.

   Heads-up—this movie trailer is full of swears and is NSFW.

verb phrase

1. swear by

   1. to name (a sacred being or thing) as one's witness or guarantee in swearing.

   2. Informal. to have great confidence in; rely on.

      He swears by his dentist.

   3. to have certain knowledge of.

      I thought I saw him leaving, but I couldn't swear by it.

2. swear off to promise or resolve to give up something.

   I've decided to swear off the internet one day a week.

   Have you sworn off red meat?

3. swear in to admit to office or service by administering an oath.

   A new president will be sworn in today.

4. swear out to secure (a warrant for arrest) by making an accusation under oath.

swear British  

/ swɛə /

verb

1. to declare or affirm (a statement) as true, esp by invoking a deity, etc, as witness

2. (foll by by)

   1. to invoke (a deity, etc) by name as a witness or guarantee to an oath

   2. to trust implicitly; have complete confidence (in)

3. to curse, blaspheme, or use swearwords

4. (when tr, may take a clause as object or an infinitive) to promise solemnly on oath; vow

5. (tr) to assert or affirm with great emphasis or earnestness

6. (intr) to give evidence or make any statement or solemn declaration on oath

7. to take an oath in order to add force or solemnity to (a statement or declaration)

8. informal to assert emphatically

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noun

1. a period of swearing

Related Words

See curse.

Other Word Forms

• reswear
  verb
• swearer
  noun
• swearingly
  adverb

Etymology

Origin of swear

First recorded before 900; Middle English sweren, Old English swerian; cognate with German schwören, Old Norse sverja; akin to Gothic swaran “to swear”; see answer

Explanation

When you take an oath about something, you swear to it, affirming its truth. Ironically, if you utter an oath, such as a curse word or obscenity, you also swear. Do you swear to put a quarter in this jar for every time you swear? The two separate meanings of swear come from branches of the same etymological tree. Both meanings have ties to Old Norse sverja, but sometime in the Middle English, the word became on one hand sweren with the meaning "to promise," while another version, swerian, became "to curse." Both might come from the idea of an oath being connected to a deity, but while one referred to truth, the other went to the dark side, negatively invoking a sacred name.

Example Sentences

Before his set, Fatboy Slim told BBC Newsbeat he was "looking forward to enjoying my songs without any swear words".

From BBC • May 22, 2026

The state does require ID when registering to vote, and residents must swear under penalty of perjury that they are eligible to vote and they are a U.S. citizen.

From Los Angeles Times • May 1, 2026

Still possible: Some eclipse-chasers swear by the sea for the best chances at a clear view of the event.

From The Wall Street Journal • Mar. 27, 2026

"It's a great contrast. The white, with the black," Trump told reporters as he showed them the ongoing work after a ceremony to swear in new the Homeland Security secretary, Markwayne Mullin.

From Barron's • Mar. 24, 2026

“Next time we meet, this torment will be over. I swear it. Ah-choo!”

From "The Interrupted Tale" by Maryrose Wood

Related Words

• affirm
• assert
• depose
• testify
• vow