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no–no

no–no /ˈnoʊˌnoʊ/ noun
plural no–no's or no–nos
no–no
/ˈnoʊˌnoʊ/
noun
plural no–no's or no–nos
Britannica Dictionary definition of NO–NO
[count] informal
: something that people are not supposed to do because it is not proper, safe, fashionable, etc.
baseball : no-hitter