imperturbable

/ˌɪmpəˈtɜːbəbl̩/

//ˌɪmpəˈtɜːbəbl̩// adj

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

The verdict

“imperturbable” is outside the top-ranked English vocabulary, used as an adjective - the kind of word writers most often double-check.

Unranked
below top-frequency English
13
letters

According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - Not capable of being, or not easily, perturbed, excited, or upset; calm and collected, even under pressure.

Key facts for imperturbable
PropertyValue
Headwordimperturbable
LanguageEnglish
Part of speechAdjective
IPA/ˌɪmpəˈtɜːbəbl̩/
Letters13
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Where “imperturbable” sits in English frequency

imperturbable falls outside the top-100,000 ranked English words, the long-tail zone of technical, archaic, or low-frequency vocabulary, exactly where readers second-guess spellings most.

Beyond rank #100,000. Source: FrequencyWords open word-frequency list.

Spelling & Dictionary Insight

The English entry for imperturbable is 13 letters long, classified as an adjective, and transcribed in the International Phonetic Alphabet as /ˌɪmpəˈtɜːbəbl̩/. It sits outside the most-frequent rank tiers, which is often why uncommon words generate more spelling variants per reader. The dominant gloss from Wiktionary reads: "Not capable of being, or not easily, perturbed, excited, or upset; calm and collected, even under pressure.".

Our edit-distance generator produced no likely misspellings for imperturbable, suggesting the orthography follows predictable English patterns. No close-neighbour confusable shows up for this headword in our dataset, suggesting its spelling stands apart enough that readers rarely confuse it with something else.

Etymologically, the entry records: PIE word *né From Late Middle English imperturbable (“undisturbed; impossible to disturb”), borrowed from Late Latin imperturbābilis, from Latin im- (variant of in- (prefix meaning ‘not’)) + Late Latin perturbabilis (“perturbable”) (from Latin perturbō (“t… The correct English form is imperturbable, spelled I-M-P-E-R-T-U-R-B-A-B-L-E.

Definition

  1. 1
    Not capable of being, or not easily, perturbed, excited, or upset; calm and collected, even under pressure.

Etymology

PIE word *né From Late Middle English imperturbable (“undisturbed; impossible to disturb”), borrowed from Late Latin imperturbābilis, from Latin im- (variant of in- (prefix meaning ‘not’)) + Late Latin perturbabilis (“perturbable”) (from Latin perturbō (“to confuse; to alarm, disturb, trouble, perturb”) + -bilis (suffix forming adjectives denoting a capacity or worth of being acted upon)). Perturbō is derived from per- (intensifying prefix) + turbō (“to agitate, disturb, unsettle, perturb; to upset”) (from turba (“disorder, disturbance, turmoil”) (possibly from Ancient Greek τῠ́ρβη (tŭ́rbē, “confusion, disorder, tumult”), either from Pre-Greek, or Proto-Indo-European *(s)twerH- (“to agitate, stir up; to urge on, propel”)) + -ō (suffix forming infinitives of regular first-conjugation verbs)). By surface analysis, im- (prefix meaning ‘not’) + perturbable.

This word in other languages

Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA). See the methodology for how each field is sourced and updated.

Frequently Asked Questions

How do you spell "imperturbable"?
"imperturbable" is spelled I-M-P-E-R-T-U-R-B-A-B-L-E. The IPA pronunciation is /ˌɪmpəˈtɜːbəbl̩/.
What does "imperturbable" mean?
As an adjective, "imperturbable" means: Not capable of being, or not easily, perturbed, excited, or upset; calm and collected, even under pressure.
How do you pronounce "imperturbable"?
The IPA (International Phonetic Alphabet) transcription for "imperturbable" is /ˌɪmpəˈtɜːbəbl̩/. 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 "imperturbable"?
PIE word *né From Late Middle English imperturbable (“undisturbed; impossible to disturb”), borrowed from Late Latin imperturbābilis, from Latin im- (variant of in- (prefix meaning ‘not’)) + Late Latin perturbabilis (“perturbable”) (from Latin pe... 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.

Using “imperturbable”

The practical upshot for anyone who landed here from a spell-check.

  • The one correct English spelling is I-M-P-E-R-T-U-R-B-A-B-L-E - every other letter order is a misspelling in standard orthography.
  • Say it as /ˌɪmpəˈtɜːbəbl̩/ (IPA); tap the speaker on the pronunciation badge to hear it where audio exists.
  • Browse more English words and confusable pairs in the same reference. English words
Data Source

Wiktionary (via kaikki.org), licensed under CC BY-SA & GFDL. Word ordering uses an open word-frequency list; misspelling variants are generated by edit-distance from the correct headword.

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

Source: FrequencyWords open word-frequency list FrequencyWords open word-frequency list