San Diego Sarah on 30 Aug 2021  •  Link

A “merry-andrew” is a jester, a cut-up or card who amuses people with a steady stream of jokes and comic banter. In extended use, “merry-andrew” is sometimes used to mean simply “fool or idiot” or, as an adjective, “foolish” or “clownish.”
The first appearance in print of “merry-andrew” used in a generic sense was by John Dryden in 1684: “Th’ Italian Merry-Andrews took their place, And quite Debauch’d the Stage with lewd Grimace”.

There has been debate over the origin of “merry-andrew” for several centuries.
The most popular theory identifies the original “merry-andrew” as Dr. Andrew Boorde (circa 1490–1549), personal physician to Henry VIII. Dr. Boorde apparently was known for his humorous bedside manner and love of a good joke (although he did not publish a popular joke collection).
Dr. Boorde’s prominence and renoun sense of humor make him a good candidate for being the original “merry-andrew.” But there is no evidence for this theory; it was simply declared as a fact in 1735 by the antiquarian Thomas Hearne (1678–1735), and subsequent attempts to prove the Boorde/”merry-andrew” equation have been fruitless.

The Oxford English Dictionary (OED) traces “merry-andrew,” based on early citations, to the Bartholomew Fair that was held every year from 1133 to 1855. (That’s an annual fair held for 700 years.
According to the City of London website, “The Fair featured sideshows, prize-fighters, musicians, wire-walkers, acrobats, puppets, freaks and wild animals. Also common at the fair was the selling of wives.” Apparently the city authorities pulled the plug on the Fair in 1855 because it had “degenerated” too far into debauchery. One can only imagine what line they finally crossed.

The OED suggests the original “merry-andrew” was a particular performer at the Bartholomew Fair in the mid- to late-17th century, most likely one, as the OED puts it, “whose persona was that of a fool” and whose stage name was “Merry Andrew.”
The OED supplies supporting citations from the period, including one dating to 1668 from the famous Diary of Samuel Pepys (“I … took her and Mercer and Deb to Bartholomew-fair, and there did see a ridiculous, obscene little stage-play called ‘Mary Andrey,” a foolish thing but seen by everybody.”)
Other quotations make it clear the performer was, in fact, male:
“Arch Merry Andrew will rend out his voice: Though his looks are but simple, & his actions the same, …By playing the fool he does get store of Coyn” (circa 1680)
and “Let’s … step to Fair of Bartlemew… Here Merry-Andrew with his Babble, Diverts the crouds of gaping Rabble” (1691).

So “merry-andrew” today, meaning a person who behaves like a clown or fool, almost certainly came from the stage name of a very successful “fool.”

http://www.word-detective.com/201…