Populism is a doctrine that appeals to the interests and conceptions (such as hopes and fears) of the general population, especially when contrasting any new collective consciousness push against the prevailing status quo interests of any predominant political sector.The word is a catch-all. Trump is somebody who is in favor of issues that the people are demanding, and where the entrenched interests have been ignoring the people.
If that makes him a populist, than I'm a populist too.
The same thing is happening in Germany.