noun · 5 senses · updated from the 2026-07-25 local source snapshot
Definitions and examples are grouped by meaning. Pronunciation, history, word forms, translations, descendants, synonyms, antonyms, derived terms, and related words appear whenever the source provides them.
Sound
Pronunciation
Each Play button uses your device's default local English voice, or a natural local fallback. The selected voice name appears after playback. This is synthesized speech, not a source recording.
US:/ɪˌɹæʃ.əˈnæl.ə.ti/
US:/ɪˌɹæʃ.ɪˈnæl.ɪ.ti/
US:/əˌɹæʃ.əˈnæl.ə.ti/
US:Recorded audio is listed in the source snapshot.
rhymes with -ælɪti
CMU ARPABET:IH2 R AE2 SH AH0 N AE1 L AH0 T IY0
Digits mark lexical stress: 1 primary, 2 secondary, 0 unstressed.
1
noun
Meaning 1
The quality or state of being irrational.
The state of being illogical or absurd.
Definition source: English Wiktionary via Wiktextract
Usage: countable, uncountable
No example sentence was provided for this meaning.
Meaning relationships
Synonyms: absurdity, illogicality, fallaciousness
Antonyms: none provided
2
noun
Meaning 2
The quality or state of being irrational.
The property of being an irrational number.
Definition source: English Wiktionary via Wiktextract
Usage: countable, uncountable
Topics: mathematics, sciences
No example sentence was provided for this meaning.
Meaning relationships
Synonyms: none provided
Antonyms: none provided
3
noun
Meaning 3
The quality or state of being irrational.
The state of being incapable of reason or abstract thought.
Definition source: English Wiktionary via Wiktextract
Usage: countable, uncountable
No example sentence was provided for this meaning.
Meaning relationships
Synonyms: unreason, mindlessness
Antonyms: none provided
4
noun
Meaning 4
Something that is irrational; the result of an illogical or absurd thought or action.
Definition source: English Wiktionary via Wiktextract
Usage: countable
No example sentence was provided for this meaning.
Meaning relationships
Synonyms: absurdity
Antonyms: none provided
5
noun
Meaning 5
the state of being irrational; lacking powers of understanding
Definition source: Princeton WordNet 3.0
No example sentence was provided for this meaning.
Meaning relationships
Synonyms: unreason
Antonyms: none provided
Broader terms: insanity
History
Etymology
From irrational + -ity. May also be analyzed as ir- + rationality.
Across languages
Translations
1 source translations are retained for this English entry.
Azerbaijani:
irrasionallıq
— state of being an irrational number