寂寞 (jì mò): одинокий

I've been in this new city for three months already. Work keeps me busy, but on weekends when I'm alone in my apartment, I still often feel very lonely.

After his wife passed away, he lives alone in the old house while his children all work in other cities, and his days are very lonely.

Even though the room was full of people, no one was willing to listen to her, and she actually felt lonelier than when she was alone.

After retiring, he does nothing but watch TV and take walks every day, with no colleagues to chat with, and he feels waves of loneliness in his heart.