Sometimes "populist" describes a political movement. Sometimes it seems to mean a policy is popular with people the speaker doesn't much like. We should be more careful about the difference.
Wanting lower immigration, cheaper energy or effective policing doesn't by itself tell us whether someone supports a dangerous form of politics. Those preferences need arguments and practical answers. Attaching a disapproving label isn't one.
There is a real definition
The political scientist Cas Mudde describes populism as an ideology that divides society between a virtuous people and a corrupt elite, with politics understood as the expression of the people's general will. That helps identify something more specific than popularity.
There are obvious dangers when a movement insists that it alone represents the real people. What happens to everyone who disagrees? What limits will it accept on its power? Will it respect the rights of opponents and institutions that refuse to do its bidding?
Those are serious questions. They should be asked of the left and the right alike.
Criticise the actual proposal
The difficulty comes when the same word is used loosely for a demand with broad support. A policy can be popular and reckless. It can also be popular and sensible. Its popularity doesn't establish either conclusion, and calling it populist doesn't explain what is wrong with it.
If lower immigration would create a particular economic cost, describe it. If an energy promise can't be delivered at the advertised price, show why. If a movement threatens constitutional protections, explain what it proposes to override.
That kind of criticism gives people something to answer. A label applied to their preference can instead sound like an objection to their having a preference at all.
I don't want to retire the word. I want its use to tell us something specific. Criticism of a movement that claims exclusive moral authority to speak for the people is different from irritation that a policy has too many supporters. Treating both as the same problem weakens the argument against the genuinely dangerous one.