Imperforable

Part of speech: adjective

Definitions

1. An entity that entirely obstructs the movement of substances, blocking any flow above, below, or through its surface
2. Not allowing anything to pass through because it cannot be pierced or penetrated
3. Completely impervious to any form of penetration or passage through its surface

Etymology: "Imperforable" is built from the prefix "in-", meaning "not" or "un-", attached to "perforable", which is itself formed from "perforate" plus the suffix "-able". So the word literally means "not able to be perforated," in other words impossible to pierce or penetrate through. The base, "perforate," traces back to the Latin "perforare," meaning "to bore through," combining "per-" ("through") with "forare" ("to bore"). English took "perforate" over several centuries, and the "-able" ending, from Latin "-abilis" via French, is a common way to form adjectives meaning "capable of being" something. Adding "in-" flips that sense into its opposite. The result is a word that is mostly technical in use, appearing in discussions of materials, membranes, seals and barriers where a surface must be sealed against passage of fluids, gases or objects. Its plain construction makes its meaning transparent: each part contributes exactly what its name suggests.

Synonyms: impermeable, impenetrable