noun, noun or participle which takes 'suru'
Rare literary word for deep worry or dread. In modern Japanese, 不安 or 心配 are far more common. May appear in older texts or formal writing.
彼の胸中には言い知れぬ憂虞が渦巻いていた。
An indescribable anxiety swirled in his heart.
将来を憂虞するあまり、夜も眠れなかった。
He worried so much about the future that he couldn't sleep at night.