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trivial; trifling; insignificant; not worth bothering with; worthless; useless; good-for-nothing
stupid; nonsensical; absurd; foolish; silly
真剣な場面でそんな下らない冗談で笑わせないで。
Don't make me laugh with silly jokes.
昨日見たテレビ番組は本当に下らなかった。
The TV show I watched yesterday was truly worthless.
彼の話は下らなくないので最後まで聞いた。
His story wasn't trivial, so I listened to the end.