1
general::
Phrase(s): swear off (something)
to pledge to avoid or abstain from something. • I’ve sworn off desserts. I am on a diet. • No dessert for me. I’ve sworn off.
McGrawhill's American Idioms And Phrasal Verbs
2
general::
Pledge to renounce or give up, as in I've sworn off cigarettes. This expression was first used for abjuring liquor in the first half of the 1800s but has since been broadened to just about anything.
American Heritage Idioms