noun
impenetrability
Technical term used in physics and philosophy to describe the property of matter that prevents two objects from occupying the same space at the same time.
物質の不可入性は、古典物理学の基本的な概念の一つである。
The impenetrability of matter is one of the fundamental concepts of classical physics.
Compound of 不可 (fuka, 'not possible') + 入 (nyū, 'enter') + 性 (sei, 'property'), literally 'the property of being unable to enter'. The exact historical derivation is uncertain, but the term is a calque from Western scientific vocabulary.