noun, plural no-nos, no-no's. Informal.

anything that is forbidden or not advisable, as because of being improper or unsafe: If you want to lose weight, rich desserts are a no-no.

Origin of no-no

1940–45, Americanism; reduplication of no1 Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for no-no

Contemporary Examples of no-no

Historical Examples of no-no

  • They're going to take No-no home, then we're all going to the movies.

    Ruggles of Red Gap

    Harry Leon Wilson

  • "No-no; I thought of that myself, and Nemu too advised it," cried Ani.

    Uarda, Complete

    Georg Ebers

  • No-no, that won't do; you mustn't talk, and you mustn't retch and gag that way, either—you'll wake up your poor brother.

    Those Extraordinary Twins

    Mark Twain (Samuel Clemens)

Word Origin and History for no-no

1942, from reduplication of no.

Online Etymology Dictionary, © 2010 Douglas Harper