Words similar to impregnable

Example sentences for: impregnable

How can you use “impregnable” in a sentence? Here are some example sentences to help you improve your vocabulary:

The dramatically rising cliff of black basalt stone made the castle impregnable to all but the most wily commander.
NYT columnist Thomas Friedman says that the U.S. airstrikes against Iraq last month rattled Saddam and showed that his system of control and intimidation is less impregnable than previously feared and weakened his support among his military protectors, the Republican Guards.
King Prithvi Narayan Shah had difficulty conquering Kirtipur, whose site atop a ridge with two high points made it virtually impregnable.
Advanced cryptography could be used to make phone conversations impregnable to wiretap and financial records invulnerable to subpoena.
Surrounded by a pair of precipitous ravines, the imposing walls of the citadel were some forty feet high and twenty feet thick, virtually impregnable.