![no-nos no-nos](https://www.tekportal.net/wp-content/uploads/2018/12/no-nos.png)
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.
n.1942, from reduplication of no.
noun, plural no-nos, no-no’s. Informal.
n.1942, from reduplication of no.