nonexistence; nothingness
A literary or classical term for the state of not existing; often used in the set phrase 烏有に帰する (to come to nothing, to be reduced to nothing). Rare in everyday speech.
His efforts came to nothing.
烏有 is an old word meaning nothingness.
fictitious person; imaginary person
Borrowed from Chinese 烏有, in which 烏 functions as an interrogative meaning “how could” and 有 means “exist”; hence “how could it exist?” and “nonexistence.”