Forsooth sounds like a dated word, but it is still part of modern English; it is primarily used in humorous or ironic contexts, or in a manner intended to play off the word's archaic vibe. Forsooth was formed from the combination of the preposition for and the noun sooth. Sooth survives as both a noun (meaning "truth" or "reality") and an adjective (meaning "true," "sweet," or "soft"), though it is rarely used by contemporary speakers and writers. It primarily lives on in the verb soothe (which originally meant "to show, assert, or confirm the truth of") and in the noun soothsayer (that is, "truthsayer"), a name for someone who can predict the future.
Examples of forsooth in a Sentence
forsooth, the rumor is true: this lovely lass and I are getting married!
you're getting married without a penny to your name—a pretty story forsooth!
First Known Use of forsooth
before the 12th century, in the meaning defined above
History and Etymology for forsooth
Middle English for soth, from Old English forsōth, from for + sōth sooth