impenetrable
im·pen·e·tra·ble/ɪmˈpɛnətɹəbəl/adjective, noun
impenetrable is spelled I-M-P-E-N-E-T-R-A-B-L-E: 12 letters and 5 syllables (im·pen·e·tra·ble). It appears 1.2 times per million words in written English, the 26,420th most frequent word form (wordfreq, 2021 data). As an adjective, impenetrable means “Not penetrable” (English Wiktionary, September 2026).
How many letters and syllables are in impenetrable?
| Letters | 12: I-M-P-E-N-E-T-R-A-B-L-E |
|---|---|
| Syllables | 5: im·pen·e·tra·ble |
| In writing | 1.2 times per million words; the 26,420th most frequent word form |
| Wrong spellings searched | none measured in search |
Sources: letters and syllables from the English Wiktionary's hyphenation or pronunciation; written frequency: wordfreq 3.1 (a 2021 snapshot of Wikipedia, subtitles, news, books, web text and social media).
How common is impenetrable?
Impenetrable appears 1.2 times per million words in written English, the 26,420th most frequent word form in the list.
Source: written frequency: wordfreq 3.1 (a 2021 snapshot of Wikipedia, subtitles, news, books, web text and social media).
How do you pronounce impenetrable?
- /ɪmˈpɛnətɹəbəl/
- /ɪmˈpɛnɪtɹəbəl/
Impenetrable has 5 syllables, split im·pen·e·tra·ble in writing.
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract). Recordings: LL-Q1860_(eng)-Vealhurl-impenetrable.wav, LL-Q1860_(eng)-Usmaan_(Middle_river_exports)-impenetrable.wav, Wikimedia Commons (author and licence on each file's page).
Forms of impenetrable
- inpenetrable
- impenetrables plural
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).
What does impenetrable mean?
The meanings the English Wiktionary records, quoted as written there (source below).
adjective
- 1
Not penetrable.
The fortress is impenetrable, so it cannot be taken.
- 2
Opaque; obscure; not translucent or transparent.
- 3
Incomprehensible; fathomless; inscrutable.
Business jargon makes this document impenetrable–I can’t understand it.
noun
- 1
A person not openly given to friendship.
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).
Impenetrable in Spanish, French, German and Portuguese
In the sense not penetrable:
| Language | Words |
|---|---|
| French | impénétrable |
| German | undurchlässig |
| Portuguese | impenetrável |
| Spanish | impenetrable |
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract). Translations are Wiktionary's, by sense; a linked word has its own PlainSpell page.
Where does impenetrable come from?
From Middle English inpenetrabel, inpenetrabyle, from Middle French impenetrable or directly from its etymon, Latin impenetrābilis. By surface analysis, im- + penetrable.
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).