irrationality

/ɪˌɹæʃ.əˈnæl.ə.ti/

//ɪˌɹæʃ.əˈnæl.ə.ti// noun

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

The verdict

“irrationality” is uncommon English (frequency #50,011 among 2,140 “I” headwords), classed as a noun. The kind of spelling people second-guess.

#50,011
frequency rank, English
2,140
“I” headwords

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - The quality or state of being irrational.

Corpus desk

Index EN-irrationality · irrationality · English

irrationality · rank #50,011 · 0 variants · 0 confusables

  • FREQ-RARE #50,011
  • LEN-MEGA 13 letters
  • VOW-7 7 vowels
  • CONFUS-0 No pairs
  • VAR-0 0 variants
  • BOOK-MID 2,140
  • PHOTO-FINISH IRI

Nearest frequency peer: IRI (-1 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 “irrationality”

Sparse band: bars invert rank so rarer forms read shorter

corpus weight

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

Source FrequencyWords open word-frequency list As of September 3, 2026
Key facts for irrationality
PropertyValue
Headwordirrationality
LanguageEnglish
Part of speechNoun
IPA/ɪˌɹæʃ.əˈnæl.ə.ti/
Letters13
Frequency rank#50,011
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Long-tail rank of “irrationality” 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).irrationalityfalls in this rarity band:

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

Scale is logarithmic (each tick is 10× rarer). Rare peers in the same band: “IRI” (#50,010), “Jamil” (#50,012), “investigational” (#50,009). Among 2,140 “I” headwords, “irrationality” is #50,011. Source: FrequencyWords open word-frequency list.

Rare enough to double-check

irrationality is uncommon English at frequency #50,011 among 2,140 “I” headwords, classed as anoun, transcribed /ɪˌɹæʃ.əˈnæl.ə.ti/. Rarity is why readers land here mid-draft. 4 senses are on record.

irrationality doesn't appear in our generated misspelling index, since its letter pattern doesn't lend itself to common typo substitutions. Our confusable-pair dataset has no match for it, since nothing in our dataset looks or sounds close enough to cause mix-ups.

Etymologically, the entry records: From irrational + -ity. May also be analyzed as ir- + rationality. The correct English form is irrationality, spelled I-R-R-A-T-I-O-N-A-L-I-T-Y.

Definition

  1. 1
    The quality or state of being irrational.
  2. 2
    The quality or state of being irrational.
  3. 3
    The quality or state of being irrational.
  4. 4
    Something that is irrational; the result of an illogical or absurd thought or action.

Recorded use

Wiktionary example

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

  1. Man introduces reason into the world of Nature, destroying irrational struggle and waste. But this activity is outside of self, distant, only reflected. Man sees this irrationality only with his intellect.

Etymology

From irrational + -ity. May also be analyzed as ir- + rationality.

Antonyms

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 "irrationality"?
"irrationality" is spelled I-R-R-A-T-I-O-N-A-L-I-T-Y. The IPA pronunciation is /ɪˌɹæʃ.əˈnæl.ə.ti/.
What does "irrationality" mean?
As a noun, "irrationality" means: The quality or state of being irrational.
How do you pronounce "irrationality"?
The IPA (International Phonetic Alphabet) transcription for "irrationality" is /ɪˌɹæʃ.əˈnæl.ə.ti/. 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 "irrationality"?
From irrational + -ity. May also be analyzed as ir- + rationality. 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 "irrationality", not the corpus desk frequency band.

Same letter count

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

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

Source: FrequencyWords open word-frequency list