禊ぐ

*⟨mi₁ so₂so₂ɡu⟩ → *⟨mi₁so₂ɡu⟩ → */misəɡu/ → /misoɡu/

From Old Japanese, continuative form misogi first attested in the Kojiki (712 CE).

Derivation likely unknown, no known phonetic spellings attested in ancient literature.

• mi is likely 水 (/mi₁/, “water”) instead of 身 (/mi₂/, “body”). See also Jōdai Tokushu Kanazukai for more detail on ancient spellings.
• sosogu (probably rendered as */səsəɡu/ in Old Japanese) is definitely 注ぐ (sosogu, “to pour over”), compare 濯ぐ (susugu, “to rinse”).

禊(みそ)ぐ • (misogu) intransitive ^†yodan

1. (Shinto, archaic) to perform misogi (purification ritual, ablution)
   • c. 759, Man'yōshū (book 3, poem 420), text here

     [...]　天(あまの)川原(かはら)尓(に)出(いで)立(たち)而(て)潔身(みそぎ)而(て)麻之乎(ましを)高山(たかやま)乃(の)石(いは)穂(ほ)乃(の)上(うへ)尓(に)伊(い)座(ませ)都類香物(つるかも) [Man'yōgana]

     [...]　天(あま)の川原(かはら)に出(い)で立(た)ちてみそぎてましを高山(たかやま)の巌(いはほ)の上(うへ)にいませつるかも [Modern spelling]

     ...ama no kawara ni ide-tachite misogite mashi o takayama no iwao no ue ni imasetsuru ka mo

     ...to purify myself and pray on the Heavenly River's shore[, ah, that] I must leave him lying among the rocks of that lofty hill![1]

• 禊(みそぎ) (misogi, “Shinto water purification ritual”)