loneliness

After moving to the big city where he knew no one, he struggled with deep loneliness.

(Chinese) 搬到谁也不认识的大城市后，他挣扎于深深的孤独感中。

Pet ownership can often help elderly people overcome feelings of isolation and loneliness.

(Chinese) 养宠物通常可以帮助老年人克服孤立感和孤独感。