A night-watchman state is a type of government that doesn't get very involved in its citizens' lives. Think of it like the police. The police's job is to watch and make sure that the neighborhood is safe at night, and step in only when needed. That's pretty much what a night-watchman state is like: the government keeps an eye on things and only steps in if there's a problem. Basically, the government provides basic services like schools, roads, and a police force, but it doesn't do any of the extra stuff - like creating new laws or taxing people - like a big government would do.