imperturbable

/ˌɪmpəˈtɜːbəbl̩/

//ˌɪmpəˈtɜːbəbl̩// adj

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

The verdict

“imperturbable” is uncommon English (outside the top frequency list), classed as an adjective. The kind of spelling people second-guess.

Unranked
below top-frequency English
13
letters

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - Not capable of being, or not easily, perturbed, excited, or upset; calm and collected, even under pressure.

Corpus desk

Index EN-imperturbable · imperturbable · English

imperturbable · unranked · 0 variants · 0 confusables

  • FREQ-UNRANKED Unranked
  • LEN-MEGA 13 letters
  • VOW-5 5 vowels
  • CONFUS-0 No pairs
  • VAR-0 0 variants
  • BOOK-THIN "I" thin
  • PHOTO-UNK Peer pending

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.

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

Long-tail rank of “imperturbable” in English

imperturbableranks outside the top 100,000 English headwords, in the long tail of specialist, archaic, or seldom-used vocabulary, exactly the territory where a reader stops mid-sentence to double-check spelling.

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

Rare enough to double-check

imperturbable is uncommon English outside the top frequency list, classed as anadjective, transcribed /ˌɪmpəˈtɜːbəbl̩/. Rarity is why readers land here mid-draft. Gloss: "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.

Recorded use

Wiktionary examples

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

  1. [T]o a vviſe man there can happen no iniury or offence at all, to moleſt the felicity of his minde, vvhich (in the Stoicks opinion) ought to bee imperturbable, and his heart adamantine.
  2. [T]he good Dominie bore all his disasters with gravity and serenity equally imperturbable. "Prodi-gi-ous!" was the only ejaculation they ever extorted from the much-enduring man.

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

Source: FrequencyWords open word-frequency list