大きい

• 大(お)っきい (okkii)

/opoki/ → /oɸoki/ → /oɸokiki/ → /owokiː/ → /oːkiː/

Appears in the Muromachi period, 1337 to 1573 CE.^[1]

From older adjective 大(おお)き (ōki, ancient reading opoki), derived as the attributive form ōki (ancient opoki) of cognate adjective ōshi (ancient oposi; attributive opoki appearing already in the Man'yōshū of 759 CE,^[2] meaning both “large” or “many”, spelled as 多(おお)し (ōshi) or 大(おお)し (ōshi), modern Japanese 多(おお)い (ōi, “many”)), in turn derived from Old Japanese adjective opo (“indistinct; of uncertain size, shape, or amount”; read as ō in modern Japanese, spelled as 凡 or 大).^[1]

• (Tokyo) おおきい (Nakadaka – )^[3]
• IPA^(key):

大(おお)きい • (ōkii) ^{←おほきい (ofokii)?}-i (adverbial 大(おお)きく (ōkiku))

1. big
2. broad, immense
3. important; crucial
   • 2020 December 3, 中舘尚人, “災害対応と不確実性のマネジメント：第1回 “ウィズ不確実性”の時代”, in 経済産業研究所 [The Research Institute of Economy, Trade and Industry]‎:

     チリ政府(せいふ)が政治(せいじ)リスクを犯(おか)して、結果(けっか)を約束(やくそく)したのは大(おお)きい。

     chiri seifu ga seiji risuku o okashite, kekka o yakusoku shita no wa ōkii.

     (please add an English translation of this example)

大(おお)きい (ōkii) and 大(おお)きな (ōkina) are essentially the same word. However, while ōkii can be used both attributively and to end a sentence, ōkina can only be used attributively, and must be followed by a noun or noun phrase.

• Correct grammar:

  あの車(くるま)は大(おお)きい。/ あの車(くるま)は大(おお)きいです。

  Ano kuruma wa ōkii./ Ano kuruma wa ōkii desu.

  That car is big.

• Incorrect grammar:

  あの車(くるま)は大(おお)きな。/ あの車(くるま)は大(おお)きなです。

  Ano kuruma wa ōkina./ Ano kuruma wa ōkina desu.

  *That car is a big __.

大(おお)きな (ōkina) can only be used attributively; a noun always follows it.

• でかい (dekai): huge
• 巨(きょ)大(だい) (kyodai): giant, gigantic

• 小(ちい)さい (chiisai), 小(ちい)さな (chiisana)