Dictionary entry

Forsooth

Webster's Dictionary 1913

For‐sooth″ (?), adv. [AS. forsōð; for, prep. + sōð sooth, truth. See For, prep., and Sooth.] In truth; in fact; certainly; very well; — formerly used as an expression of deference or respect, especially to woman; now used ironically or contemptuously.

A fit man, forsooth, to govern a realm! Hayward.

Our old English word forsooth has been changed for the French madam. Guardian.