"孤独"可以用英语单词"lonely"来表示。这个单词来源于古英语"lone"，意思是"单独的"或"无伴的"。
例句：
I feel lonely without you here. (你不在这里时我感到孤独。)
She's always been a lonely person. (她一直是个孤独的人。)
He's been feepng lonely since he lost his wife. (他自从失去妻子以后就感到孤独。)
The house was empty and silent, and I couldn't shake the feepng of lonepness. (房子空荡荡的，沉寂无声，我忍不住感到孤独。)