irrational

English

Etymology

From Latin irratiōnālis, from ir- + ratiōnālis.

Pronunciation

• enPR: ĭră'sh(ə)nəl, IPA^(key): /ɪˈɹæʃ.(ə.)nəl/

• Audio (Southern England):

  (file)

• Rhymes: -æʃənəl

Adjective

irrational (comparative more irrational, superlative most irrational)

1. Not rational; unfounded, nonsensical or wrong-headed.

   an irrational decision

   • July 18, 2012, Scott Tobias, AV Club The Dark Knight Rises[1]

     Where the Joker preys on our fears of random, irrational acts of terror, Bane has an all-consuming, dictatorial agenda that’s more stable and permanent, a New World Order that’s been planned out with the precision of a military coup.

2. (mathematics, arithmetic, number theory, not comparable) Of a real number, that cannot be written as the ratio of two integers.

   Antonym: rational

   The number π is irrational.

   Hyponyms: transcendental, uncomputable

Derived terms

• irrationalism
• irrationalist
• irrationalistic
• irrationality
• irrationalization
• irrationalize
• irrationally
• irrationalness
• irrational number
• nonirrational

Collocations

nouns

• irrational fear
• irrational belief
• irrational behavior
• irrational thought
• irrational thinking
• irrational urge
• irrational anger
• irrational jealousy
• irrational desire
• irrational hope
• irrational exuberance
• irrational feeling
• irrational person
• irrational system

adverbs

• completely irrational
• utterly irrational
• wholly irrational
• seemingly irrational
• totally irrational
• quite irrational
• too irrational

Translations

unfounded or nonsensical

• Armenian: իռացիոնալ (hy) (iṙacʻional)
• Asturian: irracional
• Bulgarian: неразумен (bg) (nerazumen), безразсъден (bg) (bezrazsǎden)
• Catalan: bèstia (ca), irracional (ca)
• Chinese:

  Mandarin: 不合理 (zh) (bùhélǐ)

• Danish: irrationel
• Dutch: irrationeel (nl), irrationele (nl), onzinnig (nl), onzinnige (nl), onredelijk (nl), onredelijke (nl)
• Esperanto: malracia
• Finnish: epälooginen (fi), irrationaalinen (fi)
• French: irrationnel (fr)
• Galician: irracional
• German: irrational (de), irrationell, unvernünftig (de)
• Greek:

  Ancient: ἄλογος (álogos)

• Hungarian: észszerűtlen (hu), irracionális (hu)
• Irish: aingiallta
• Italian: irrazionale (it)
• Japanese: 不合理な (ja) (fugōri na), 無理な (ja) (muri na), 理不尽な (ja) (rifujin na), ばかげた (bakageta), 筋違いな (ja) (sujichigai na)
• Korean: 불합리한 (bulhamnihan)
• Macedonian: нера́зумен (nerázumen), безра́суден (bezrásuden)
• Manx: neuresoonagh
• Maori: heahea
• Norwegian:

  Bokmål: irrasjonell

  Nynorsk: irrasjonell

• Plautdietsch: onveninftich
• Polish: nieracjonalny (pl), irracjonalny (pl)
• Portuguese: irracional (pt)
• Romanian: irațional (ro), nerațional (ro)
• Russian: нерациона́льный (ru) (neracionálʹnyj), иррациона́льный (ru) (irracionálʹnyj)
• Serbo-Croatian:

  Cyrillic: и̏рациона̄лан, не̏разӯман

  Roman: ȉracionālan (sh), nȅrazūman (sh)

• Spanish: irracional (es)
• Swedish: irrationell (sv)
• Tagalog: atbang, maatbang
• Telugu: అసంబద్ధము (te) (asambaddhamu)
• Vietnamese: bất hợp lý

mathematics: of a number

• Armenian: իռացիոնալ (hy) (iṙacʻional)
• Bulgarian: ирационален (bg) (iracionalen)
• Catalan: irracional (ca)
• Chinese:

  Mandarin: 無理數 / 无理数 (zh) (wúlǐshù)

• Czech: iracionální (cs)
• Danish: irrational
• Dutch: irrationaal (nl), irrationale (nl)
• Esperanto: neracionala
• Finnish: irrationaalinen (fi)
• French: irrationnel (fr)
• German: irrational (de)
• Greek: άρρητος (el) (árritos)

  Ancient Greek: ἄρρητος (árrhētos)

• Hindi: अपरिमेय (hi) (aprimey)
• Hungarian: irracionális (hu)
• Icelandic: óræður m
• Japanese: 無理数 (ja) (murisū)
• Korean: 무리수 (ko) (murisu)
• Maori: kewha
• Norwegian:

  Bokmål: irrasjonal

  Nynorsk: irrasjonal

• Polish: niewymierny
• Portuguese: irracional (pt)
• Russian: иррациона́льный (ru) (irracionálʹnyj)
• Swedish: irrationell (sv)
• Tagalog: ditagwayin
• Vietnamese: số vô tỉ (vi)

The translations below need to be checked and inserted above into the appropriate translation tables. See instructions at Wiktionary:Entry layout § Translations.

Translations to be checked

• Indonesian: ^{(please verify)} irasional (id), ^{(please verify)} tak masuk akal

Noun

irrational (plural irrationals)

1. A real number that can not be expressed as the quotient of two integers, an irrational number.
   • 1946, Bertrand Russell, History of Western Philosophy, I.24:

     The square root of 2, which was the first irrational to be discovered, was known to the early Pythagoreans, and ingenious methods of approximating to its value were discovered.

Translations

irrational number

• Bulgarian: ирационално число (iracionalno čislo)
• Icelandic: óræð tala f
• Korean: 무리수 (ko) (murisu)
• Polish: liczba niewymierna f
• Tagalog: bilang na ditagwayin

Further reading

• “irrational”, in OneLook Dictionary Search.
• “irrational”, in Merriam-Webster Online Dictionary, Springfield, Mass.: Merriam-Webster, 1996–present.
• “irrational”, in The American Heritage Dictionary of the English Language, 5th edition, Boston, Mass.: Houghton Mifflin Harcourt, 2016, →ISBN.
• “irrational”, in Collins English Dictionary.
• “irrational” (US) / “irrational” (UK) in Macmillan English Dictionary.

German

Alternative forms

• irrationell

Pronunciation

• IPA^(key): /ˈɪʁat͡si̯onaːl/, /ɪʁat͡si̯oˈnaːl/

• Audio:

  (file)

Adjective

irrational (strong nominative masculine singular irrationaler, comparative irrationaler, superlative am irrationalsten)

1. irrational

Declension

Positive forms of irrational

number & gender		singular			plural
		masculine	feminine	neuter
predicative		er ist irrational	sie ist irrational	es ist irrational	sie sind irrational
strong declension (without article)	nominative	irrationaler	irrationale	irrationales	irrationale
	genitive	irrationalen	irrationaler	irrationalen	irrationaler
	dative	irrationalem	irrationaler	irrationalem	irrationalen
	accusative	irrationalen	irrationale	irrationales	irrationale
weak declension (with definite article)	nominative	der irrationale	die irrationale	das irrationale	die irrationalen
	genitive	des irrationalen	der irrationalen	des irrationalen	der irrationalen
	dative	dem irrationalen	der irrationalen	dem irrationalen	den irrationalen
	accusative	den irrationalen	die irrationale	das irrationale	die irrationalen
mixed declension (with indefinite article)	nominative	ein irrationaler	eine irrationale	ein irrationales	(keine) irrationalen
	genitive	eines irrationalen	einer irrationalen	eines irrationalen	(keiner) irrationalen
	dative	einem irrationalen	einer irrationalen	einem irrationalen	(keinen) irrationalen
	accusative	einen irrationalen	eine irrationale	ein irrationales	(keine) irrationalen

Comparative forms of irrational

number & gender		singular			plural
		masculine	feminine	neuter
predicative		er ist irrationaler	sie ist irrationaler	es ist irrationaler	sie sind irrationaler
strong declension (without article)	nominative	irrationalerer	irrationalere	irrationaleres	irrationalere
	genitive	irrationaleren	irrationalerer	irrationaleren	irrationalerer
	dative	irrationalerem	irrationalerer	irrationalerem	irrationaleren
	accusative	irrationaleren	irrationalere	irrationaleres	irrationalere
weak declension (with definite article)	nominative	der irrationalere	die irrationalere	das irrationalere	die irrationaleren
	genitive	des irrationaleren	der irrationaleren	des irrationaleren	der irrationaleren
	dative	dem irrationaleren	der irrationaleren	dem irrationaleren	den irrationaleren
	accusative	den irrationaleren	die irrationalere	das irrationalere	die irrationaleren
mixed declension (with indefinite article)	nominative	ein irrationalerer	eine irrationalere	ein irrationaleres	(keine) irrationaleren
	genitive	eines irrationaleren	einer irrationaleren	eines irrationaleren	(keiner) irrationaleren
	dative	einem irrationaleren	einer irrationaleren	einem irrationaleren	(keinen) irrationaleren
	accusative	einen irrationaleren	eine irrationalere	ein irrationaleres	(keine) irrationaleren

Superlative forms of irrational

number & gender		singular			plural
		masculine	feminine	neuter
predicative		er ist am irrationalsten	sie ist am irrationalsten	es ist am irrationalsten	sie sind am irrationalsten
strong declension (without article)	nominative	irrationalster	irrationalste	irrationalstes	irrationalste
	genitive	irrationalsten	irrationalster	irrationalsten	irrationalster
	dative	irrationalstem	irrationalster	irrationalstem	irrationalsten
	accusative	irrationalsten	irrationalste	irrationalstes	irrationalste
weak declension (with definite article)	nominative	der irrationalste	die irrationalste	das irrationalste	die irrationalsten
	genitive	des irrationalsten	der irrationalsten	des irrationalsten	der irrationalsten
	dative	dem irrationalsten	der irrationalsten	dem irrationalsten	den irrationalsten
	accusative	den irrationalsten	die irrationalste	das irrationalste	die irrationalsten
mixed declension (with indefinite article)	nominative	ein irrationalster	eine irrationalste	ein irrationalstes	(keine) irrationalsten
	genitive	eines irrationalsten	einer irrationalsten	eines irrationalsten	(keiner) irrationalsten
	dative	einem irrationalsten	einer irrationalsten	einem irrationalsten	(keinen) irrationalsten
	accusative	einen irrationalsten	eine irrationalste	ein irrationalstes	(keine) irrationalsten