The field is impenetrable and virtually indestructible. This cactus often forms thickets in coastal hammocks which can be impenetrable and spiny. It often has several trunks and can form impenetrable thickets. Reptarenaviruses and mammarenavirus are separated by an impenetrable species barrier. She also has the power to generate nearly impenetrable invisible force fields. Classically, an object hitting an impenetrable barrier will not pass through. The woods are thick and dark and impenetrable. They're heavy on jargon and impenetrable calculation, murky and heavy on theory. Joffre was generally taciturn and a man of impenetrable calm, sometimes interspersed with furious anger. The Ladakhi forces laid siege to the almost impenetrable Tsaparang. Everywhere else the roads were mere tracks which were impenetrable to artillery. Minoru's power is the ability to protect himself inside an impenetrable shell. Hard spheres are characterized as non-interacting and impenetrable spheres. This mixture was thought to be completely water impenetrable. But two hours later, it also proves to be emotionally impenetrable.