noun
unsellable property; real estate with negative value
Jocular term playing on 不動産 (real estate). Refers to property that is a burden rather than an asset, often because it cannot be sold or costs more to maintain than it is worth.
田舎の空き家は負動産になりかねない。
A vacant house in the countryside can easily become an unsellable property.
相続した土地が負動産で、固定資産税だけがかさむ。
The inherited land is a negative-value property, and only the property tax keeps piling up.
A jocular coinage blending 負 (negative, burden) with 不動産 (real estate), playing on the homophony of 不 and 負.