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painful; heartrending; trying
oppressive; suffocating; miserable
失恋の切ない思いを歌にした曲が人気を集めた。
A song about the painful feelings of heartbreak became popular.
故郷を離れる日は切なかった。
The day I left my hometown was heartrending.
彼女の歌声は切なくないと感じる人もいる。
Some people don't find her singing voice painful.