A boundary is a limit that defines what you are and are not willing to accept in a relationship, situation, or interaction. It is not a wall, walls keep everything out. A boundary defines the terms under which genuine connection is possible.
Boundaries come from values. They arise from the recognition of what you need to function, what you are willing to accept from others, and what you are not. They are information about you, not judgments about others.
Setting limits is commonly experienced as unkind or selfish, particularly by people who were taught that care means self-sacrifice, or who developed people pleasing patterns as a way of maintaining safety. This perception is inaccurate. Limits that are communicated clearly and kindly are a feature of honest relationships.
The alternative to setting limits is not kindness. It is resentment. Resentment accumulates when needs go unmet, when agreements are repeatedly broken, or when the cost of staying in a relationship is consistently higher than it needs to be.
Effective limits require internal clarity (knowing what you actually need), communication (stating limits clearly without excessive justification), and consistency (following through when limits are not respected).