In BDSM, a safeword is a code word, series of code words or other signal used by a person to communicate their physical or emotional state, typically when approaching, or crossing, a physical, emotional, or moral boundary.^[1] Some safewords are used to stop the scene outright, while others can communicate a willingness to continue, but at a reduced level of intensity.

Safewords are usually agreed upon before playing a scene by all participants, and many organized BDSM groups have standard safewords that all members agree to use to avoid confusion at organized play events.^[2] The most common safeword system is the "traffic light" system, in which "red" means "stop", "amber" or "yellow" means "proceed with caution", and "green" means "more, please!"^[3]

Those who practise the more permissive philosophy of risk-aware consensual kink may abandon the use of safewords, especially those that practice forms of edgeplay or extreme forms of dominance and submission. In such cases, the choice to give up the use of safewords is a consensual act on the part of the bottom or submissive.^[4] Some couples may also feel that they do not need one, depending on the practices involved.