English
impregnableness
From impregnable + -ness.
Formed from impregnable + -ness
Proto-Indo-European *gʰed- ‘to find’
Old French imprenable
Middle English imprenable
English impregnable
Today it means
noun The state of being impregnable; impregnability.
Language periods are conventional ranges, not dates for this word.
Etymograph / impregnableness