Definition - What does Hard Limit mean?
A hard limit is a limit that is set before BDSM play that cannot be changed. A hard limit is something that either partner cannot or will not participate in whether for physical, emotional, or other reasons.
Kinkly explains Hard Limit
In BDSM, partners set limits so that play remains safe and no personal boundaries are crossed without permission. For example, while BDSM may include whipping or caning, a submissive may set these types of play as a hard limit because they're on blood thinning medication or simply because they don't enjoy it. Limits are set before engaging in any play to avoid any confusion, injury, or unnecessary fights and arguments. If a hard limit is broken it is a reason to end the scene immediately.