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sluggish; languid; listless; heavy (heart, legs, etc.); dull
bothersome; tiresome; pain-in-the-ass
今日は一日中体がだるくて仕方ない。
My body has felt sluggish all day today.
風邪をひいてしまって体がだるいです。
I caught a cold and my body feels sluggish.
だるい体を引きずりながら歩いた。
I walked dragging my sluggish body.