The phrase "most authorizing" can be replaced with several synonyms, depending on the context. If referring to something that gives the greatest amount of power or legal authority, alternatives include "most empowering," "most enabling," "most legitimizing," or "most sanctioning." In a more general sense, "most influential," "most persuasive," or "most convincing" can also take the place of "most authorizing" to describe something that is highly influential or carries significant weight. Ultimately, the appropriate synonym for "most authorizing" will depend on the specific nuances of the intended meaning and the context in which it is used.