The feeling of loneliness or desolation; a sense of being alone or emotionally empty (noun form of '寂しい').
引っ越してきたばかりで寂しさを感じることが多い。
Since I just moved here, I often feel lonely.
成功しても寂しさが消えるわけではないと気づいた。
I realized that even success doesn't necessarily get rid of the feeling of loneliness.
夜の静けさが寂しさを一層強めた。
The quiet of the night intensified the sense of loneliness.