Merriam-Webster Collegiate Dictionary - demagogue

 I. noun  also demagog  Etymology: Greek demagogos, from demos people (perhaps akin to Greek daiesthai to divide) + agogos leading, from agein to lead — more at tide, agent  Date: 1648  1. a leader who makes use of popular prejudices and false claims and promises in order to gain power  2. a leader championing the cause of the common people in ancient times  • ~ry noun  • demagogy noun  II. verb  also demagog  (-gogued; also -goged; -goguing; also -goging)  Date: 1656  intransitive verb to behave like a ~  transitive verb to treat (as an issue) in a demagogic manner