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abhorrent; abominable; detestable; disgusting; horrid; repugnant
あの夜の出来事は忌まわしかった。
What happened that night was truly abominable.
過去の忌まわしい体験が今も夢に出てくる。
My abhorrent past experiences still appear in my dreams.
あの選択があまりにも忌まわしくて後悔しても後悔しきれない。
That choice was so repugnant that no amount of regret feels like enough.