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

With a certain visa, people must swear to their intent to marry within 90 days of arrival on foreign shores.

From Los Angeles Times • May 20, 2026

It was like getting the vicar to swear.

From BBC • May 8, 2026

“Ibrahim was here a few days ago, actually,” he told me in 2021, “and I swear I could still not look him in the eye.”

From Slate • Apr. 19, 2026

No dramatic rejection, no moment where you swear them off.

From Salon • Apr. 10, 2026

“I swear I saw Ivan with you when you walked up.”

From Anya and the Nightingale by Sofiya Pasternack

Related Words

• affirm
• assert
• depose
• testify
• vow