Joke
noun, の adjective
When you discuss something superfluous you aren't being serious, you're telling a joke.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
つまらない冗談に係わってるひまはないんだよ。
I have no time to waste on a stupid joke.
トーフグはポッドキャストで冗談ばかり言っているが、時々冗談の通じない人からいかりのメールをもらうことがあります。
Tofugu likes joking on their podcast, but sometimes they get angry emails from people who don't get the jokes.
冗談はヤメてよ！何でフレンチレストランなんて行きたいの？私達の柄じゃないっしょ。飲めればどこでもいいじゃん？違う？
Stop joking around. Why do you want to go to a French restaurant? We shouldn’t break our pattern. If we’re just going drinking, anywhere is fine, right?