- The definition of a no no is something that should not be done or something that is against the rules.
An example of a no no is eating cookies before dinner after your mom said not to eat them.
Taking this cookie is a no-no.
no-no definition by Webster's New World
Origin: ; from No! No!, as said in admonishing a young child
no-no definition by American Heritage Dictionary
noun pl. no-noes Informal
- Something unacceptable or impermissible: “Even though his company wasn't the one involved in the case, what he did is considered a definite no-no” (Mike Royko).
- A social blunder; a faux pas.