Sorrow, grief, or melancholy; a poetic/literary term referring to deep sadness or a troubled feeling.
彼女の目にはどことなく憂いがあり、話しかけづらかった。
There was a certain melancholy in her eyes, making it hard to approach her.
老画家は憂いを帯びた風景画を好んで描いた。
The elderly painter liked to paint landscapes tinged with melancholy.
憂いに沈む夜を過ごしながらも、彼は前を向こうと努めた。
Even while spending nights sunk in sorrow, he tried to look forward.