impregnable(too strong to be defeated or overcome, see also: invincible) adjective [UK: ɪm.ˈpreɡ.nəb.l̩] [US: ˌɪm.ˈpreɡ.nəb.l̩]A territory is the set of intersections that a player has managed to encircle with his stones in such a way that it has become impregnable. = Un territorio es el conjunto de intersecciones que un jugador ha logrado rodear con sus piedras de tal manera que se ha vuelto inexpugnable.