Irrational — Meaning, Definition & Synonyms

adjective noun /i-ˈra-sh(ə-)nəl/ ir·ra·tio·nal

Meaning & Definition of Irrational

Irrational (adjective)

  1. not rational
  2. lacking usual or normal mental clarity or coherence
  3. not endowed with reason or understanding

Irrational (noun)

  1. an irrational being
  2. irrational number

Irrational (adjective) — Senses, Synonyms & Antonyms

  1. not using or following good reasoning

    "it's irrational to think that you can continue to consume an excess of calories and not gain weight"

    similar: fallacious, illegitimate, illogical, inconsequent, inconsequential, invalid, nonrational, unreasonable, unreasoning, unsound, weak
    related: eristic, misleading, sophistic, specious, half-baked, ill-advised, misguided, unconsidered, unreasoned, inconsistent, absurd, asinine, foolish, meaningless, nonsensical, preposterous, reasonless, senseless, silly, Kafkaesque, odd, peculiar, strange, surreal, unusual, weird, insane, mad, nutty, wacky, disordered, disorganized, rambling, random, unconvincing, inexplicable, unaccountable, unexplainable
    opposite: logical, rational, reasonable, sound, valid, well-founded, well-grounded
    near: commonsense, sane, sensible, sober, wise, enlightened, informed, just, justified, reasoned, ordered, organized, clear, cogent, compelling, convincing, credible, persuasive, plausible, satisfying, solid, certain, sure, true, confirmed, corroborated, demonstrated, established, substantiated, validated

Synonyms, Thesaurus & Another Word for Irrational

The most common words with a similar meaning to Irrational:

fallacious, illegitimate, illogical, inconsequent, inconsequential, invalid, nonrational, unreasonable, unreasoning, unsound, weak

Antonyms & Opposite Words for Irrational

Words with the opposite meaning of Irrational:

logical, rational, reasonable, sound, valid, well-founded, well-grounded

Related Words for Irrational

eristic, misleading, sophistic, specious, half-baked, ill-advised, misguided, unconsidered, unreasoned, inconsistent, absurd, asinine, foolish, meaningless, nonsensical, preposterous, reasonless, senseless, silly, Kafkaesque, odd, peculiar, strange, surreal, unusual, weird, insane, mad, nutty, wacky

Near Antonyms of Irrational

commonsense, sane, sensible, sober, wise, enlightened, informed, just, justified, reasoned, ordered, organized, clear, cogent, compelling, convincing, credible, persuasive, plausible, satisfying, solid, certain, sure, true, confirmed, corroborated, demonstrated, established, substantiated, validated

Word Forms of Irrational

Derived words: irrationality (noun), irrationally (adverb)

Origin & Etymology of Irrational

Middle English, from Latin irrationalis, from in- + rationalis rational

First known use: 14th century

Words & Phrases Containing Irrational

irrational number

Frequently Asked Questions about Irrational

What does "Irrational" mean?

"Irrational" means not rational. As an an adjective and a noun, it is defined as: not rational.

What is another word for "Irrational"?

Other words for "Irrational" include fallacious, illegitimate, illogical, inconsequent, inconsequential, invalid, nonrational and unreasonable. The best synonym depends on which meaning of "Irrational" you intend.

What are different ways to say "Irrational"?

There are 49 words and phrases with a similar meaning to "Irrational". Common alternatives include fallacious, illegitimate, illogical, inconsequent, inconsequential, invalid, nonrational, unreasonable, unreasoning and unsound.

What is the opposite of "Irrational"?

Antonyms of "Irrational" include logical, rational, reasonable, sound, valid, well-founded and well-grounded. Near antonyms include commonsense, sane, sensible and sober.

How do you use "Irrational" in a sentence?

Examples of "Irrational" in a sentence: "it's irrational to think that you can continue to consume an excess of calories and not gain weight".

Is "Irrational" a noun, verb, or adjective?

"Irrational" can be used as an adjective and a noun, depending on the context.

How do you pronounce "Irrational"?

"Irrational" is pronounced /i-ˈra-sh(ə-)nəl/ and divided into syllables as ir·ra·tio·nal.

What is the origin of the word "Irrational"?

"Irrational" comes from Middle English, from Latin irrationalis, from in- + rationalis rational. First known use: 14th century.