Sometimes a word that really means "No" is needed, but the actual word "no" isn't available for one reason or another. A "safe word" can be aimed at the person who interacts with you, to underscore that you really need to hit the emergency brake. Or it could be meant for a third party that might come to your aid. Or both. Of course, any word can be used as a safe word. And the concept is not limited to sexual situations either. Commonly used by undercover operatives of all kinds while wearing a wire or being in a bugged room. Compare Safe, Sane, and Consensual. Contrast Trust Password.