怠(だる)いsluggish, languid, listless, heavy (heart, legs, etc.), dull, bothersome, tiresome

高熱(こうねつ)のせいで体(からだ)がだるいです。

I feel sluggish because of the high fever. {sluggish, languid, listless, heavy (heart, legs, etc.), dull, bothersome, tiresome}

睡眠(すいみん)不足(ぶそく)なので全身(ぜんしん)が怠(だる)い気(き)がします。

I feel sluggish all over because I'm not getting enough sleep. {sluggish, languid, listless, heavy (heart, legs, etc.), dull, bothersome, tiresome}

微熱(びねつ)があってだるかったので、会社(かいしゃ)を休(やす)みました。

I took a day off from work because I had a slight fever and felt sluggish. {sluggish, languid, listless, heavy (heart, legs, etc.), dull, bothersome, tiresome}

右腕(みぎうで)が怠(だる)いと訴(うった)えたところで、監督(かんとく)は心配(しんぱい)してくれないだろう。

Even if I complain about my right arm feeling sluggish, the coach probably won't worry about me. {sluggish, languid, listless, heavy (heart, legs, etc.), dull, bothersome, tiresome}

マラソン選手(せんしゅ)といえども、マラソンの後(あと)はしっかり足(あし)がだるくなるそうです。

Even for marathon runners, it seems that their legs become quite heavy and sluggish after a marathon. {sluggish, languid, listless, heavy (heart, legs, etc.), dull, bothersome, tiresome}