swear on
To promise something is true by mentioning something very important to you, like your mother's life or the Bible.
Meanings
To make a formal or legal oath by placing one's hand on a sacred object (such as a Bible) as a sign of sincerity.
"The witness swore on the Bible before giving his testimony in court."
"I do solemnly swear on the Constitution of the United States."
— Traditional U.S. presidential oath of office formula.
To promise informally that something is absolutely true by invoking something precious to you.
"I swear on my life that I never touched your phone."
Used in legal, religious, and everyday informal contexts. Common collocations include 'swear on the Bible,' 'swear on my mother's grave,' and 'swear on my life.' The casual version ('I swear on my life') is very common in informal speech.
Commonly used with
Forms
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Synonyms
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