The Oxford Thesaurus An A-Z Dictionary of Synonyms - swear v.

1) depose, aver, asseverate, declare, insist, assert, solemnly affirm or state, testify, promise, take an oath, undertake, vow, avow, vouchsafe, warrant, pledge, give one's word, agree: He swore he had not done any such thing. 2) curse, blaspheme, imprecate, use profanity, utter profanities, execrate, Colloq cuss: Priscilla stopped her ears at the men's swearing. 3) swear by. trust (in) , believe in, rely on, have confidence in, count on: The colonel swears by the same old fountain-pen he has used for years and will use no other. 4) swear off. forswear, renounce, abjure, go off, forgo, shun, avoid, give up, eschew, forsake, throw over: Brian tells me he's sworn off alcohol for a while.