swear by


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]

QUIZZES

DON’T VACILLATE! VANQUISH THIS WORD OF THE DAY QUIZ!

It’d be a real faux pas to miss this quiz on the words from August 3–9, 2020!
Question 1 of 7
What does “vacillate” mean?
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.