曰く

From Old Japanese.

The く (ku)-nominalization of the classical verb 言ふ (ifu), modern 言う (iu, “to say”).[1]

• (Tokyo) い​わく [íꜜwàkù] (Atamadaka – [1])[1]
• (Tokyo) いわく [ìwákú] (Heiban – [0])[1]
• IPA^(key): [iɰᵝa̠kɯ̟ᵝ]

曰(いわ)く • (iwaku) ^{←いはく (ifaku)?}

1. (used adverbially) what a person or source says; according to

   カール・マルクス曰(いわ)く「あらゆる社(しゃ)会(かい)の歴(れき)史(し)は階(かい)級(きゅう)闘(とう)争(そう)の歴(れき)史(し)である」だそうです。

   Kāru Marukusu iwaku “Arayuru shakai no rekishi wa kaikyū tōsō no rekishi de aru” da sō desu.

   Karl Marx says that "The history of society is the history of class struggles."

   • Analects, kanbun kundoku

     曾(そう)子(し)曰(いわ)く、吾(われ)、日(ひ)に三(み)たび吾(わ)が身(み)を省(かえり)みる。

     Sōshi iwaku, ware, hi ni mitabi waga mi o kaerimiru.

     Zengzi said: I reflect on myself thrice a day.

2. a reason, story
   • 1955 May, Ango Sakaguchi, Murder Case of the Baseball Pitcher(投手殺人事件):

     曰(いわ)くありですな。

     Iwaku ari desu na.

     There's a story behind it for sure.

Do not confuse the kanji 曰 (“say”) with 日 (“sun; day”).

• 曰(いわ)く言(い)い難(がた)し (iwaku iigatashi)

The く (ku)-nominalization of the classical verb 宣ふ (notamafu → notamau, “to say”, archaic),[1][2][3] from 宣(の)り給(たま)う (noritamau),[1][2][3] compound of 宣(の)り (nori, “連(れん)用(よう)形(けい) (ren'yōkei, “stem or continuative form”) of the verb 宣(の)る (noru, “to say, declare”)”) + たまう (tamau, an honorific).

• (Tokyo) のたま​わく [nòtámáꜜwàkù] (Nakadaka – [3])
• IPA^(key): [no̞ta̠ma̠ɰᵝa̠kɯ̟ᵝ]

曰(のたまわ)く • (notamawaku) ^{←のたまはく (notamafaku)?}

1. (honorific, used adverbially) ...says
   • 1596, Contemptus mundi[4]

     Von arujino notamauaqu: qui seqitur me, non ambulat in tenebris, sed babebit lumen vitæ. Ioan. 8. Vareuo xitǒ monoua yamigiuo yucazu: tada jumiǒ no ficariuo motçu bexi to nari.

     The Lord says: Qui seqitur me, non ambulat in tenebris, sed babebit lumen vitæ. (John 8[:12]) ‘Whoever follows me will never walk in darkness but will have the light of life.’

The く (ku)-nominalization of verb 言ふ (ipu, “to say”).[1]

曰く (ipaku) (kana いはく)

1. (used adverbially) what a person or source says
   • c. 759, Man’yōshū, book 4, poem 619:

     ...幼婦常 言雲知久 手小童之 哭耳泣管 俳徊 君之使乎 待八兼手六

     ...tawayame₁ to₂ ipaku mo siruku tawarapa no₂ ne no₂mi₂ naki₁tutu tamoto₂pori ki₁mi₁ ga tukapi₁ wo mati ya kanetemu

     ...as the type of (weak) woman spoken of as a tawayame (手弱女), I cry all the time like a child, wandering around and waiting for an envoy with a message from you.

• Japanese: 曰く (iwaku)