More correctly, Zanny (Italian zanni, a buffoon; Latin sannio, “sanna” means a grimace, and “sanneo” one who makes grimaces).
…for indeed, He's like the zani to a tumbler That tries tricks after him to make men laugh.
“He belonged to one of those dramatic companies called zanni, who went about the country reciting and acting.” —John Inglesant, chap. xxvii
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894