A rationalist is the opposite of a demagogue.
Well, an antonym for demagogue can be: faithful leader, trusted one, or a faithful person you know that is a leader...
The opposite (antonym) of antonym is synonym. An antonym is a word that means the opposite. A synonym is a word that means the same thing, or nearly the same thing, for a given context.
One antonym is DISAGREEMENT.
quetion(s)