term used in bondage play with one or more partners which lets the partners know that play needs to stop or slow down immediately. A safety word can be any word a person desires, all partners should know everyone's safety words before starting play.
Her safety word was 'ballet', I tightened my grip on her throat and watched for the movement of her lips to tell me she'd had enough.
a word used in conjunction with s&m, consensual torture, bondage, etc - so that when you say "no" or "stop" in the heat of the moment, the other person can disregard it - the safety word is the serious-i-mean-it-now time-to-stop word. usually something ridiculus like Alabama.
"Why did Jesus die on the cross? Because he forgot his safety word."