verb
retract, revoke, renounce, disavow, disclaim, abjure, deny, take back, cancel, back down, back out, withdraw, rescind, abrogate, forswear, contradict, repudiate, abnegate, annul, void, countermand, recall, call back, disown, unsay, nullify, repeal, draw in one's horns*, eat crow*, be of another mind*, eat humble pie*, eat one's words*, eat one's hat*; see also abandon 1.
Antonyms acknowledge*, maintain, proclaim.