Definition of impenetrable in English:

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Pronunciation: /imˈpenətrəb(ə)l/


1Impossible to pass through or enter: a dark, impenetrable forest
More example sentences
  • To my horror though, I did not catch myself upon hitting the wall, but proceeded to pass through it into impenetrable darkness.
  • So the Romans decided it was not the primitive barbarians known as the Caledonii who had defeated them, but the vast impenetrable forest covering the country now known as Scotland.
  • The island is full of impenetrable virgin forest ill-suited to bikes, leaving the last leg to be completed on foot.
dense, thick, overgrown
archaic thickset
1.1 Physics (Of matter) incapable of occupying the same space as other matter at the same time.
impervious, impermeable, indestructible, solid, thick, unyielding;
informal bulletproof
2Impossible to understand: impenetrable interviews with French intellectuals
More example sentences
  • Music industry insiders tend to litter their conversation with talk of turnover, market share and the impenetrable jargon of contract negotiations.
  • The wording of the document is really very easy to understand; it is not written in the usual impenetrable verbiage of the Treaties.
  • It misfires because almost every page of it is weighed down by nearly impenetrable academic jargon.



Pronunciation: /imˌpenətrəˈbilədē/
Example sentences
  • The problems of secrecy, impenetrability, accountability, and representativeness, which have long been a focus for concern within the Community, are not addressed simply by giving added powers to the European Parliament.
  • The dizzying power struggles in the household contribute to a plot that starts out pointedly enigmatic, and flirts with chaos and impenetrability before resolving itself into gentle ambiguity.
  • Modern man among vast natural expanses, exhilarating waterfalls next to calm cherry blossoms, and the impenetrability of a forest alongside the openness of a bare field are some examples of the contrasts pictured.


Pronunciation: /imˈpenətrəblē/
Example sentences
  • But, whereas many people fear it as some kind of unapproachably dense and impenetrably difficult cornerstone of the Western canon, few seem to realise that it's actually very funny - hilarious at points, even.
  • Never mind the impenetrably named programs, what about the stuff that really matters: letters, music, video, e-mails, and all those useful nuggets picked up from the web?
  • Since that opening, in 1985, a system of arts funding has developed that is impenetrably complex, often manifestly unfair, and always unaccountable.


Late Middle English: via French from Latin impenetrabilis, from in- 'not' + penetrabilis 'able to be pierced', from the verb penetrare (see penetrate).

For editors and proofreaders

Syllabification: im·pen·e·tra·ble

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