勢い

From classical noun 勢(いきほ)ひ (ikifofi),

rom=ikifofu

連(れん)用(よう)形(けい) (ren'yōkei, “stem or continuative form”) of the verb 勢(いきほ)ふ (ikihofu).

• (Tokyo) いきおい [ìkíóꜜì] (Nakadaka – [3])^[1]
• IPA^(key): [ikʲio̞i]

勢(いきお)い • (ikioi) ^{←いきほひ (ikifofi)?}

1. force; power; strength; energy; vigor

   勢(いきお)いよくボールを投(な)げる

   ikioi yoku bōru o nageru

   throw the ball with full force

   (literally, “throw the ball with excellent vigour”)

2. momentum; spur of the moment

   Synonym: 調子

   勢(いきお)いで買(か)ったやつ

   ikioi de katta yatsu

   spur-of-the-moment purchase

勢(いきお)い • (ikioi) ^{←いきほひ (ikifofi)?}

1. naturally; inevitably
   • 1914, 夏目漱石 [Natsume Sōseki], chapter 42, in こゝろ [Kokoro], 下 先生と遺書 [Sensei's Testament]:

     Ｋ(ケイ)は私(わたくし)より背(せい)の高(たか)い男(おとこ)でしたから、私(わたくし)は勢(いきお)い彼(かれ)の顔(かお)を見上(みあ)げるようにしなければなりません。

     Kei wa watakushi yori sei no takai otoko deshita kara, watakushi wa ikioi kare no kao o miageru yō ni shinakereba narimasen.

     K was a taller man than I, so naturally I had to look up to see his face.

• “勢い”, in 漢字ぺディア [Kanjipedia]‎^[1] (in Japanese), The Japan Kanji Aptitude Testing Foundation, 2015–2026