Ex cathedra means "from the chair" in Latin. It is commonly used to describe statements made by officials in positions of authority, such as religious leaders or government officials. Synonyms for this phrase may include "authoritatively," "definitively," "formally," "officially," and "dogmatically." These words all share a similar connotation of speaking with absolute authority and as the final word on a subject. It is important to note that using these phrases requires a level of confidence and expertise, and may come across as arrogant if not used in context appropriately. Choosing the right synonym can give more emphasis and clarity to the speaker's point of view.