Lapideous is a rarely used word that refers to something that is characterized by or resembling stone. While it is a very precise word, there are a number of synonyms that can be used to describe something that possesses similar qualities. These synonyms include stony, rock-like, rocky, stone-like, and petrous. Each of these words can be used to describe something that is hard, durable, and dense like stone. While these words do not precisely convey the same meaning as lapideous, they are all viable alternatives that can be used to convey similar ideas and evoke similar images in the minds of readers.