Wiktionary
a. Resembling a fortress in shape or impregnability.
Usage examples of "fortresslike".
Cicero saw the condemned man at his very luxurious and fortresslike residence on the Carinae, he discovered that Gaius Rabirius had other ideas for his defense.
From the roadway (had anyone been standing there) the fortresslike building's silhouette against the jewel-strewn indigo of the vaulted sky was not unlike that of some ancient Crusader castle, its bell towers rearing up like horns on the head of a creature risen from the deep.
When the fifth woman had left his private rooms, which were a minifortress within the fortresslike presidential palace compound, Corazon knew what he would do.
The ridges zigged and zagged their way out toward a fortresslike island, a low wall running about it, several metallic structures visible beyond.