Is this an inside joke?

这到底是不是一个内部玩笑？

youdao

PI: That's an inside joke in figure skating.

PI：有一个流传在花样滑冰行内的笑话。

youdao

We're not going to tell you what we're talking about. It's an inside joke.

我们不会告诉你我们所说的内容，这是圈儿内的秘密。

youdao

Judges seem to relish what has become, more or less, an inside joke among colleagues.

WSJ: Here's a Funny Idea: Medicare Laws That Are Easy to Read

The deniability at the start of that last sentence is an inside joke.

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It was a sign of the times that nobody knew whether EBE was an inside joke or was actually serious.

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