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swear by

Definition of swear by

  1. :  to have or express a lot of confidence in (something) :  to say that (something) is very good or useful <She swears by this diet.>

Word by Word Definitions

  1. :  to utter or take solemnly (an oath)

    :  to assert as true or promise under oath

    :  to assert or promise emphatically or earnestly

  1. :  oath, swearword

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