impermissible

/ˌɪmpɝˈmɪsɪbl/

//ˌɪmpɝˈmɪsɪbl// adj

By · According to Wiktionary data (CC BY-SA) ·

"impermissible" is a 13-letter English headword indexed on PlainSpell.

The verdict

“impermissible” is uncommon English (frequency #62,991 among 2,140 “I” headwords), classed as an adjective. The kind of spelling people second-guess.

#62,991
frequency rank, English
2,140
“I” headwords

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - Not permissible; not to be permitted or allowed.

Corpus desk

Index EN-impermissible · impermissible · English

impermissible · rank #62,991 · 0 variants · 0 confusables

  • FREQ-RARE #62,991
  • LEN-MEGA 13 letters
  • VOW-5 5 vowels
  • CONFUS-0 No pairs
  • VAR-0 0 variants
  • BOOK-MID 2,140
  • PHOTO-FINISH imperator

Nearest frequency peer: imperator (-2 rank slots)

Read with this headword: Spelling guide for this pattern

Desk codes from Wiktionary headword shape, FrequencyWords rank tier, confusable-pair count, generated misspelling depth, letter-cohort book size, and photo-finish peer. Not a difficulty grade.

Long-tail ranks near “impermissible”

Sparse band: bars invert rank so rarer forms read shorter

corpus weight

What this shows Long-tail view: where “impermissible” sits against similarly uncommon English ranks.

Source FrequencyWords open word-frequency list As of September 3, 2026
Key facts for impermissible
PropertyValue
Headwordimpermissible
LanguageEnglish
Part of speechAdjective
IPA/ˌɪmpɝˈmɪsɪbl/
Letters13
Frequency rank#62,991
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Long-tail rank of “impermissible” in English

Every-word frequency runs from the handful of words we use constantly (left) to the long tail used once in a blue moon (right).impermissiblefalls in this rarity band:

#1#100#1K#10K#100K
← used constantlyrarely used →

Ticks step logarithmically, so each one marks a roughly tenfold drop in how often the word turns up. Rare peers in the same band: “imperator” (#62,989), “imprudent” (#62,993), “immobilize” (#62,988). Among 2,140 “I” headwords, “impermissible” is #62,991. Source: FrequencyWords open word-frequency list.

Rare enough to double-check

impermissible is uncommon English at frequency #62,991 among 2,140 “I” headwords, classed as anadjective, transcribed /ˌɪmpɝˈmɪsɪbl/. Rarity is why readers land here mid-draft. Gloss: "Not permissible; not to be permitted or allowed.".

impermissible doesn't appear in our generated misspelling index, since its letter sequence doesn't invite the usual edit-distance slips. No confusable counterpart is on file for this word, a sign it's visually distinctive enough not to be mixed up with another word.

Etymologically, the entry records: From im- + permissible. The correct English form is impermissible, spelled I-M-P-E-R-M-I-S-S-I-B-L-E.

Definition

  1. 1
    Not permissible; not to be permitted or allowed.

Recorded use

Wiktionary example

These source excerpts show how impermissible appears in context. They illustrate usage; the definition above remains the entry’s reference meaning.

  1. Their use was “impermissible not because it is unwise or ineffective, but because [federal law]^([sic]) does not allow it”, the decision explained.

Etymology

From im- + permissible.

Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA); frequency ordering uses the FrequencyWords open word-frequency list (2018 English corpus, MIT). See the methodology for how each field is sourced and updated.

Frequently Asked Questions

How do you spell "impermissible"?
"impermissible" is spelled I-M-P-E-R-M-I-S-S-I-B-L-E. The IPA pronunciation is /ˌɪmpɝˈmɪsɪbl/.
What does "impermissible" mean?
As an adjective, "impermissible" means: Not permissible; not to be permitted or allowed.
How do you pronounce "impermissible"?
The IPA (International Phonetic Alphabet) transcription for "impermissible" is /ˌɪmpɝˈmɪsɪbl/. Click the speaker icon on the pronunciation badge above to hear it spoken aloud where audio is available.
What is the origin of the word "impermissible"?
From im- + permissible. See the full etymology section above for more details.
Is PlainSpell free to use?
Yes, PlainSpell is a completely free word reference. You can look up definitions, pronunciations, confusable pairs, homophones, and spelling corrections across 5 languages without any sign-up or subscription.

Similar English words by spelling shape

Same letter count and similar misspelling depth for "impermissible", not the corpus desk frequency band.

Same letter count

Frequency-ranked English headwords with 13 letters (nearest by frequency rank).

interrogative#63,001intransigence#63,002educationally#62,859devastatingly#62,837

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list