/ Dictionary / Index I impenetrability: Meaning and Definition of Find definitions for: im•pen•e•tra•bil•i•ty Pronunciation: (im-pen"i-tru-bil'i-tē, im"pen-), [key] — n. the state or quality of being impenetrable. that property of matter by virtue of which two bodies cannot occupy the same space simultaneously. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: impenetrability (Thesaurus) impending impenetrable Related Content Daily Word Quiz: acquiesce Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language