No churning means that you don't need to use an ice cream maker. An ice cream maker has a paddle/dasher that churns (mixes) the cream as it freezes. A no churn recipe is nice because you don't have to find room in your kitchen for another appliance. Some ice cream recipes require you to cook some ingredients (milk, cream, egg, sugar) to make a custard before it is frozen. That can be good, but I'm all about using less steps.