A vague pronoun used to refer to unspecified things or multiple items when specifics are not needed.
机の上に何々が置いてあるから、片付けておいてください。
There are some things on the desk, so please tidy them up.
授業で何々の違いについて説明がありました。
In class there was an explanation about the differences between such-and-such things.
この本の何々の章を読んで来てください。
Please read such-and-such chapter of this book.
Used when listing or giving examples to mean 'and so on' or 'such-and-such' without specifying details.
今日はケーキや何々を買って帰ろう。
Let's buy cake and such things on the way home today.
イベントでは、歌やダンス、何々が行われます。
At the event there will be singing, dancing, and other activities.
書類には『会議での何々について』とだけ書いてあった。
The document only said 'about such-and-such at the meeting.'
An interjection expressing surprise or asking for confirmation (e.g., 'What? / Wait, what did you say?').
A: 明日結婚するんだ。 B: えっ、なになに？本当？
A: I'm getting married tomorrow. B: What—wait, really?
『給料が上がる』って？なになに、どういうこと？
'My salary is going up'? Wait, what do you mean?
電話で『今忙しい』って言われて、なになにと聞き返した。
They told me on the phone 'I'm busy now,' so I asked, 'What?'
An interjection used as a preface when about to read a document or letter (e.g., 'Now then, let's see...').
さて、何々…。まずは挨拶から読みます。
Now then... First I'll read the greetings.
何々、差出人は匿名ですね。内容を読みます。
Hm, the sender is anonymous. I'll read the contents.
An interjection used to dismiss or brush off someone's comment or concern (like 'it's nothing' or 'don't worry about it').
A: ごめんね。 B: 何々、気にしないで。
A: Sorry. B: Oh, it's okay; don't worry about it.
手伝おうか？ 何々、もう大丈夫だよ。
Shall I help? Oh no, it's fine already.