impregnable

It was a ponderous labyrinth of bolts, locks, and steel doors, making it an almost impregnable fortress.

When Sherman reached those earthworks, he thought them the most impregnable he had ever seen.

His place in the hearts of most Thai is central and impregnable.

Meanwhile, the Russians made the salient virtually impregnable.

But it was really the uemployment data that turned out to be his impregnable fortress.

The Prussians held an apparently impregnable position on the Landgrafenberg, a precipitous hill which commanded the town.

These are truths—fixed facts, that quaint theory and exhausted moralising, are impregnable to, and fall harmlessly before.

This done, the fort was declared impregnable, and the tired travellers turned in, well assured of complete security.

At the beginning of this year Antwerp, supposed to have been impregnable, surrendered to Marshal Gerard.

Here, at least, was a citadel impregnable by right-hand defections or left-hand extremes.