a person, especially a politician, who strives to appeal to ordinary people who feel that their concerns are disregarded by established elite groups.Oxford Dictionary Online
To expand a little more on that definition, a populist is someone that says, “Hey, these fancy pants people don’t care about your problems, but I do.”
Historically populist leaders are associated with dictators who overthrow the governmental system and put themselves in the position of power. Often the masses, the common people, are suffering and a populist leader places all the blame on a prospering elite group that is somehow untouched by the suffering of the “rest of us”.
The idea behind the populist approach is to recognize that power in numbers can take you to the top. By appealing to the masses and pitting them against a small, easy-to-blame target the populist leader promises to lead them into prosperity.
One thing to be careful of… Populist leaders, as they strive to appeal to ordinary folk, may sometimes twist the facts to make things look better or worse. If current or historical events as they really are do not paint a compelling enough picture, the facts become fair game to warp things into something more appealing.