Does such a word that teeters, or overlaps, between abstract and concrete exist?
For instance, consider violence. It's a term that varies in meaning or definition from person to person until the type of violence is given. And while we may have different understandings of what violence is, a major portion of people recognize when violence is occurring. So terms like violence overlap between the concrete and abstract.
This is very different when it comes to terms like faith, which is almost entirely abstract.