Unperforable is a word that indicates something that cannot be punctured or perforated. There are several synonyms for this word that express the same idea, including impenetrable, impermeable, undrillable, imbreakable, nonporous, and imperviable. All these words indicate that a material or object cannot be pierced, penetrated, or broken through. For example, an unbreakable glass bottle might be described as impenetrable, while an impermeable material might be used to seal a container that needs to be protected from air or liquid. Depending on the context and application, it may be more appropriate to use one of these synonyms in place of unperforable.