dem·a·gogue / ˈdeməˌgäg/ • n. a leader who seeks support by appealing to popular desires and prejudices rather than by using rational argument. ∎  (in ancient Greece and Rome) a leader or orator who espoused the cause of the common people.DERIVATIVES: dem·a·gog·ic / ˌdeməˈgäjik; -ˈgägik; -ˈgōjik/ adj.dem·a·gogu·er·y / ˈdeməˌgägərē/ n.dem·a·go·gy / ˈdeməˌgäjē; -ˌgōjē/ n.ORIGIN: mid 17th cent.: from Greek dēmagōgos, from dēmos ‘the people’ + agōgos ‘leading’ (from agein ‘to lead’).

demagogue leader of the people or of a popular faction. XVII. — Gr. dēmagōgós, f. dêmos people + agōgós leader, f. ágein lead.
So demagogic XIX. demagogy XVII. — Gr. dēmagōgíā; see -Y 3.