comic performer, 1580s, from French zani, from Italian zani, zanni "a zany, clown," originally Zanni, Venetian dialect variant of Gianni, pet form of Giovanni "John." A stock character in old comedies, he aped the principal actors.
1869, from zany (n.). Related: Zanily; zaniness.
Amusingly or ridiculously strange (1918+)