The Collaborative International Dictionary of English v.0.48:

Zany \Za"ny\, n.; pl. Zanies. [It. zanni a buffoon,
   merry-andrew, orig. same as Giovanni John, i. e., merry John,
   L. Ioannes, Gr. ?, Heb. Y[=o]kh[=a]n[=a]n, prop., the Lord
   graciously gave: cf. F. zani, fr. the Italian. Cf.
   Jenneting.]
   A merry-andrew; a buffoon.
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         Then write that I may follow, and so be
         Thy echo, thy debtor, thy foil, thy zany. --Donne.
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         Preacher at once, and zany of thy age.   --Pope.
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