THESAURUS
Gainsay
abjure, assert the contrary, be contrary to, belie, call into question, challenge, combat, contest, contradict, contravene, controvert, counter, cross, deny, disaffirm, disallow, disavow, disclaim, disown, disprove, dispute, fight, forswear, impugn, join issue upon, negate, negative, not accept, not admit, nullify, oppose, oppugn, rebut, recant, refuse to admit, refute, reject, renounce, repudiate, resist, retract, revoke, take back, take issue with, traverse, withstand
ROGET THESAURUS
Gainsay
Negation
VB
deny, contradict, contravene, controvert, give denial to, gainsay, negative, shake the head, disown, disaffirm, disclaim, disavow, recant, revoke, dispute, impugn, traverse, rebut, join issue upon, bring in question, call in question, give the lie in his throat, give one the lie in his throat, deny flatly, deny peremptorily, deny emphatically, deny absolutely, deny wholly, deny entirely, give the lie to, belie, repudiate, set aside, ignore, rebut, qualify, refuse, recuse.