indemonstrable
adj. 不能证明的
例句
His definitions do not always define, his axioms are not always indemonstrable, his demonstrations require many axioms of which he is quite unconscious.
他的定义并不总是下了定义的,他的公理并不总是不可证明的,他的证明需要许多他还没有完全意识到的公理。