What is the major distinguishing characteristic between flexible and rigid constitutions?

The major distinguishing characteristic between flexible and rigid constitutions is the amendment procedure. A flexible constitution is easily amended and changed through the ordinary legislative process, while a rigid constitution requires a more difficult and elaborate process for amendments. In a rigid constitution, the amendment process is often more difficult, requiring a special majority or a referendum to make changes to the constitution. This is meant to ensure that fundamental principles and values of the constitution are not easily changed, and that they reflect the will of the people. Conversely, a flexible constitution can be easily changed by the legislative process, which may be desirable for some countries that need to adapt to changing circumstances quickly.