Authoritative simply means to have due authority, or to have an air of authority. An authoritative person demonstrates authority, she or he is commanding. It also means being recognized or accepted as true, reliable or official. This adjective can also refer to showing or having impressive knowledge about a particular field, or having a confident quality of a respected person. Authoritarian, on the other hand, means being characterized by or to be favoring obedience to authority, as against individual freedom. It also refers to the person who favors authoritarian policies.
