A leader who obtains power by means of impassioned appeals to the emotions and prejudices of the populace.
A leader of the common people in ancient times.
tr.v.
dem·a·gogued also dem·a·goged, dem·a·gogu·ing also dem·a·go·ging, dem·a·gogues also dem·a·gogs Usage Problem To speak about (an issue, for example) in the manner of a demagogue.
[Greek dēmagōgos, popular leader : dēmos, people; see dā- in Indo-European roots + agōgos, leading (from agein, to lead; see ag- in Indo-European roots).]
Usage Note: Among the nouns that the Usage Panel is loath to see used as a verb is demagogue, meaning "to speak about something in the manner of a demagogue." Ninety-four percent reject it in the sentence The President will demagogue Medicare, unwilling to acknowledge that fundamental reforms need to be made. Resistance to the use of traditional nouns as verbs is sometimes strong, especially when the novel usages are associated with business or bureaucratic jargon.
[dem-uh-gog, -gawg] 
noun, verb, -gogued, -gogu⋅ing.