Since a friend of mine asked me about this after being confused by the translation Jisho.org gives for this word, I'll leave a summary of the meaning that I found in Japanese when I googled it, here. This word originally means making tea with the same leaves twice (and thus making it taste bland). It is also colloquially used as doing the exact same thing twice, hereby taking all the fun out of it. I hope this helps!
A bit more than just rehash
Since a friend of mine asked me about this after being confused by the translation Jisho.org gives for this word, I'll leave a summary of the meaning that I found in Japanese when I googled it, here. This word originally means making tea with the same leaves twice (and thus making it taste bland). It is also colloquially used as doing the exact same thing twice, hereby taking all the fun out of it. I hope this helps!