And thus she maketh Absolon hire ape, And al his ernest turneth til a jape. (286-287)
Is it really Alisoun who makes Absolon appear foolish? Or is it his own refusal to give up the courtship in the face of continued rejection? There is a way in which Alisoun turns Absolon's earnestness into a joke, in her refusal to take it seriously herself.
. . . Nicholas shal shapen him a whyle This sely jalous housbond to bigyle. (300-301)
"Sely" means stupid, but it also means innocent and harmless, the implication being that the innocent lack guile. It's a perfect word to describe John, whose "sely"-ness derives from a somewhat innocent nature that fails to see the treachery in others.
Ye, blessed be alwey a lewed man That noght but only his bileeve can! (352-353)
John's defense of the "lewed" or "unlearned" is rendered foolish by the ease with which he is duped by Nicholas only a few lines later. If John had probed further into Nicholas's story, perhaps he would not have been so easily tricked.