Today, zany is mainly an adjective meaning "bizarre" or "goofy", and that meaning was first attested in the 1610s, but for more than three decades before that it was a noun referring to a type of masked clown in old comedies that mimicked the actions of another. That, through Middle French zani, is a borrowing from Italian Zanni, which was a dialectal nickname for Giovanni, who apparently was a recurring character in many of the comedies. The proper noun Giovanni comes from Latin Iohannes, which comes from Ancient Greek Ioannes, which ultimately derives from the Hebrew word Yohanan, which translates to "God is gracious". As I've explained in a previous post, this origin makes the word zany related to names as diverse as Janice, Evan, Juan, Nina, Ivan, Hank, and Jonas, which is really cool.
Adam Aleksic, a rising sophomore studying linguistics and government at Harvard University, has been described as the internet's sixth most famous etymologist. He also has disturbing interests in politics, vexillology, geography, board games, conlanging, and law.