noun, plural no-nos, no-no's. Informal.
Origin of no-no
Examples from the Web for no-no
Not all scientists agree that artificial sweeteners are a no-no when it comes to your health and diet.
Converting at birth the children of non-Jewish mothers is now a no-no.In Italy, a Traditional Jewish Lifestyle is Disappearing|Anna Momigliano|December 13, 2013|DAILY BEAST
The point is, nobody knows what's next on the Hamas no-no list, which is almost always enforced before it is pronounced.
Raising taxes is a no-no with Grover, so that leaves raising the eligibility age.
This is a no-no in the LDS church, to say the least, and as a result Scott spent a year or so “disfellowshipped” for his sins.Turning Spotlight on Mitt Romney Siblings Could Help Humanize GOP Nominee|Michelle Cottle|May 30, 2012|DAILY BEAST
"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)
They're going to take No-no home, then we're all going to the movies.Ruggles of Red Gap|Harry Leon Wilson
1942, from reduplication of no.