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Synonyms

swear by

Idioms  

  1. Have great reliance on or confidence in, as in She swears by her personal physician . [Early 1800s]

  2. 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]

  3. 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.

Even those who swear by the broccoli concoction say they can’t be sure that they are benefiting from anything other than a placebo effect.

From The Wall Street Journal • Feb. 12, 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

Some people swear by writing a song every day and finishing it, even if it’s bad.

From Los Angeles Times • Dec. 1, 2025

So what about some of the other health targets that many of us swear by?

From BBC • Jul. 25, 2025

‘I swear, by my blood on this blade, and by each of my three souls that I will find the Mountain of the World Spirit. Or die trying.’

From "Wolf Brother" by Michelle Paver

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.