gainsay
ɡeɪnˈseɪ
verb
deny or contradict (a fact or statement).
the impact of the railways cannot be gainsaid
deny,dispute,disagree with,argue with,dissent from,contradict,repudiate,declare untrue,challenge,oppose,contest,counter,fly in the face of,disprove,debunk,explode,discredit,refute,rebut,brush aside,shoot full of holes,shoot down (in flames),disaffirm,controvert,confute