from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. Slang A person regarded as eccentric or irrational: "a catchy pop portrait of a wacko who talks to himself in French” ( Phoebe Hoban).
  • adj. Wacky.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • adj. amusingly eccentric or irrational
  • n. An amusingly eccentric or irrational person.
  • interj. hurrah

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • n. a person who is regarded as eccentric or mad


Alteration of wacky.
(American Heritage® Dictionary of the English Language, Fourth Edition)
wack(y) + -o (Wiktionary)



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  • whassitsell?

    December 10, 2007

  • Also the name of the best store in Los Angeles.

    December 10, 2007