It means they are nearby somewhere, and have to keep looking around. I'll give you an example, I lost my AirPods last week, didn't lose them technically, like misplaced them in my house. On Find My it kept saying that they are nearby and keep looking. I searched the entire house and couldn't find them. And then one night I parked my car on the driveway and as I passed along the garbage bins, I got this notification that AirPods have been found (I had notify when found) turned on. And then I realized they were in the garbage bin. What I mean to say is that it could be in any random place where you will never think of.