* Limitation: This is the most common and general noun form, meaning a restriction or constraint.
* Limit: This noun refers to the point beyond which something cannot go.
* Limits: This is the plural form of "limit."
* Boundedness: This word emphasizes the concept of being confined or restricted.
* Restriction: This noun signifies a rule or condition that limits something.
The best option will depend on the specific sentence and meaning you are trying to convey.