Rootlessness is the feeling or the state of having nowhere that is really home. It is the noun that sits beside rootless: if someone is rootless, what they live with is rootlessness. People use it in writing about moving country, war, or growing up between cultures — the ache of not being fully from here or from there. It is a serious, slightly formal word; you will meet it in essays and news more than in chat. You can speak of a sense of rootlessness, or the rootlessness of a whole group of people.