swear upon

English

Alternative forms

• swear on

Verb

swear upon (third-person singular simple present swears upon, present participle swearing upon, simple past swore upon, past participle sworn upon)

1. (transitive, formal) To take an oath on someone or something.

   to swear upon the Holy Writ to speak the truth

   • 1610–1611 (date written), William Shakespeare, “The Tempest”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, →OCLC, [Act II, scene ii]:

     I'll swear upon that bottle to be thy true subject, for the liquor is not earthly.