Printable Version
Pronunciation: im-pêr-vi-ês Hear it!

Part of Speech: Adjective

Meaning: 1. (with to) Impenetrable, impermeable. 2. Insusceptible, incapable of being affected.

Notes: Only the letter V stands between impervious and imperious, so be careful of your spelling. This word is the negative of pervious "permeable, penetrable", a rarely used adjective. The adverb and noun are the obvious ones: imperviously and imperviousness. Impervium is a word introduced in the 30s referring to a science-fiction element that is virtually indestructible.

In Play: Today's Good Word is less frequently used in reference to physical imperviousness: "While flak jackets are impervious to bullets, they are not impervious to the impact of bullets." It is more often used in the figurative second sense: "Phil Anders is impervious to the reasonings of women's rights and the #metoo movement."

Word History: English impervious is a remake of Latin impervius "impassible", based on an assimilated form of in- "not, un-" + pervius "permeable". Pervius is a combination of per "through" + via "way, road" + an adjective suffix. Via comes from PIE wegh- "go, move, carry, especially by vehicle". It also produced vehere "to carry". Vehiculum "cart, carriage", which English borrowed for its vehicle, is a derivative of vehere. Wegh came to English via its Germanic ancestors as way, weight, and wagon. Weigh slipped into the language at a time when things were weighed by primitive scales, comprising two plates hanging by chains balanced on a fulcrum. Presumably, weight was a measure of how many weights an object could carry. (Lest he think we are impervious to gratitude, let's all thank William Hupy for yet another fascinating Good Word.)

Dr. Goodword,

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