Named peril policy is how it’s called in the Real Estate Industry the insurance policies that specify the perils it covers. Under a named peril policy, if anything that isn’t listed in the policy happens to your house, the insurance will not cover it.
Here's a scenario: Let’s say you have a named peril policy and in it, listed, are lightning strikes and fires. If a flood happens and damages your house, or if someone throws a rock in your window, the insurance is not obligated to provide any help, because those perils were not "named" listed on your policy.
The opposite of that is an Open perils policy, where everything that is NOT listed is covered.
So know it that, whenever you're looking at homeowner's insurance and someone says "this is a named peril policy", it means you have to be pretty aware of what is listed and what perils your house is most likely to be in danger of.