ora ora ora オラオラオラ

If you've ever watched JoJo's Bizarre Adventure, specially Stardust Crusaders, you've probably already heard Kujō Jotarō 空条 承太郎 and his stand, Star Platinum, screaming ora ora ora オラオラオラ at everyone they punched.

And you might have asked yourself: what does this ora ora ora mean in Japanese?

Anime: JoJo no Kimyou na Bouken ジョジョの奇妙な冒険 - Part 3: Stardust Crusaders (Chapter 123, 奇虫襲撃！の巻)

• ora ora ora ora ora ora ora ora ora!!!
  オラオラオラオラオラオラオラオラオラ！！！
  (twelve ora's.)
• dodododododo
  ドドドドドド
  *sound effect for punches*
  (onomatopoeia.)

The answer is: not much.

• Single Ora オラ
• In JoJo

Single Ora オラ

In Japanese, a single ora オラ is a way to call for somebody's attention. A yell, like "oi!" or "ayy!" or "hey!" or whatever.

It gets used toward children or animals when they're doing something improper. You could translate it as "watch out" or "stop that!" depending on the situation. Sometimes it's used to make people look at stuff, so you can translate it as "look (at that)!" in such cases.

• ora, miro
  オラ、見ろ
  Hey, look [at that.]
  Oy, check that out.
  I told you that was gonna happen, look!

Sometimes, ora オラ is used as a kakegoe 掛け声, something you said while doing something, like "heave-ho!" or "one, two, three!" Except in this case is something you say while punching someone.

In English, this could be translated as "take this!" for example.

Manga: Saiki Kusuo no Psi-Nan, 斉木楠雄のΨ難 (Chapter 114, Ψ閥の御曹司現る！)

• oraa!!
  オラァ！！
  [Take this]!
• doka'
  ドカッ
  *strike sound effect*

The word kora コラ is similar, but is used more to scold than to tell people to look at things.

The word hora ホラ, too, is similar, but it's used only to show people things, like "look," or "see."

Manga: Mahoujin Guruguru 魔法陣グルグル (Chapter 4, ジェム平原)

• Context: Kukuri ククリ correctly drew a "magic circle," mahoujin 魔法陣, but only after countless failures. She shows the failed magic circles to Nike ニケ.
• hora
  ほら
  See.
• ...
• (the face in one of the circles is called a henohenomoheji へのへのもへじ.)
• sappari sappari
  さっぱりさっぱり
  (in this series, the sappari fairy is summoned whenever something silly happens.)
  • sappari
    さっぱり
    Completely. Specially in the sense of completely clean. (mimetic word.)
    (typically used as an abbreviation of)
  • sappari wakaranai
    さっぱりわからない
    To completely not know.
    To have absolutely no idea.
• shippai
  しっぱい
  Failure.

In JoJo

The way it's used in the oraoraoraoraora of JoJo is kind of like "take this! And this! And this! And this! And this! And this! And this!" and so on as he goes on punching.

More literally, you could think of it as Jotarō telling his punching bag, err, victim, I mean, target to "look" at the punches, a call of attention, or something like that. It just boils down to Jotarō screaming something with each punch.

To make it clear: oraoraoraora doesn't really mean anything in Japanese.

Similarly, muda muda muda muda 無駄無駄無駄無駄 is used by another character and also doesn't mean much either.

Some Japanese words gain different meanings when they're said twice (reduplication), but this isn't the case here, this is merely repetition.