Touchstone, in As You Like It, is the Duke's fool. He has remained at court with the Duke's daughter Rosalind after Senior's bansihment to the Forest of Arden by his own brother Frederick. Touchstone's job as fool is to be a "whetstone" by which others may sharpen their wits through his foolery. However, as in most of Shakespeare's plays, and as the traditional job of the fool allows, Touchstone is much more clever than most of those around him. In his "pancakes and mustard" speech to Rosalind and Celia, what Touchstone is saying is that a knight who swears by his honor for good pancakes and mustard must have no honor. He is hinting at the lack of honor of Celia's father, the unlawful Duke Frederick, who has just summoned Rosalind and Celia to watch a wrestling match, where Rosalind will meet Orlando.
Noooooooooo he is not the duke's fool , he is the court's fool ..