Gainsay

We cannot gainsay that he is honest.

The contumacious student dared to gainsay his teacher.

Now, however, that they had received the command to rest and sleep (and to gainsay the Father's commands was a thing that would never have entered their minds), they were willing enough to obey, and had hardly laid themselves down before they fell into a deep slumber, from which neither awoke until the light of day had long been shining upon the world, and the Father stood beside them bidding them rise and follow him.

[…]vve are able with playne demonſtration to proue, and vvith reaſon to perſvvade that in tymes paſt our fayth vvas alike, that then vve preached thinges correſpondent vnto the forme of faith already publiſhed of vs, ſo that none in this behalfe can repyne or gayneſay vs.

The supreme court, therefore, may assume jurisdiction over subjects and between parties, not allowed by the constitution, and there is no power in the federal government to gainsay it.

So she had, cried Scrooge. You’re right. I will not gainsay it, Spirit. God forbid!

Know then that in the time of the Great Rebellion (the history of which by the learned Lord Clarendon I most earnestly commend to your attention) this Manor of Baskerville was held by Hugo of that name, nor can it be gainsaid that he was a most wild, profane, and godless man.

And there was something childlike about Griffith, too, even in his Matlock days, as a deceptively sharp 'simple country lawyer,' a big-kid boyishness that did not mask his intelligence or gainsay his authority.