gainsay的过去式和过去分词

Gainsay \Gain`say"\ (? or ?; 277), v. t. [imp. & p. p.
{Gainsaid} (? or ?); p. pr. & vb. n. {Gainsaying}.] [OE.
geinseien, ageinseien. See {Again}, and {Say} to utter.]
To contradict; to deny; to controvert; to dispute; to forbid.

I will give you a mouth and wisdom which all your
adversaries shall not be able to gainsay nor resist.
--Luke xxi.
15.

The just gods gainsay
That any drop thou borrow'dst from thy mother,
My sacred aunt, should by my mortal sword
Be drained. --Shak.