swear by
Idioms-
Have great reliance on or confidence in, as in She swears by her personal physician . [Early 1800s]
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Also, swear to . Have reliable knowledge of, be sure of, as in I think she was going to the library but I can't swear to it . [Mid-1700s]
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Take an oath by, as in I swear by all the saints in heaven . [Early 1200s]
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
To start things off, here are three personal-finance principles that I’ve come to swear by through my own wins and losses.
From MarketWatch ● Aug. 4, 2026
“At the end of the day, the government is going to go with systems that have been deployed, where combatant commanders swear by the fact that they want one of what we have,” Mengucci said.
From Barron's ● Jan. 15, 2026
People swear by it, but a lot of these things have a placebo effect.
From The Wall Street Journal ● Jan. 5, 2026
For some people it's a reward after exercise while for others, it's the main attraction and many regulars swear by it, convinced that 15 minutes of intense heat does wonders for their body and mind.
From BBC ● Dec. 29, 2025
“In the name of the Council, we swear by the River Styx to grant your reasonable request as long as it is within our power.”
From "The Last Olympian" by Rick Riordan
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
