Inexpugnable

[Slava]

No, that's not a typo for inexpungeable, it's a word unto itself. It means impregnable, incapable of being moved by force: an inexpugnable position; inexpugnable hatred.

Interestingly, the word it comes from, expugnable, has two pronunciations; pyoon or puhg. This one appears to have only the puhg variant.

[Audiendus]

There are several -pugn words in English: expugn, impugn, oppugn. They are all derived from Latin pugnare, to fight.