Together with a deep moat its strong walls rendered it virtually impregnable.

"The pincushion is virtually impregnable when the fleets are nearly even."

Theboro 's skin is virtually impregnable to its native enemies.

The city is virtually impregnable, and sooner or later you would have to deal with Arai's forces at your rear.

He avoids these as virtually impregnable, designed to resist heavy artillery.

The same defense system created a virtually impregnable information bubble around the Posleen forces.

On the hockey rink they make a virtually impregnable goalie.

With a garrison of 500 men, the castle was virtually impregnable without a large attacking army.

The Temple was an enormous, virtually impregnable building, guarded day and night.

It has a perfect situation, high above the river and what used to be a tidal harbour - virtually impregnable.