In business, disinvestment means to sell off certain assets such as a manufacturing plant, a division or subsidiary, or product line. Disinvestment is sometimes described as the opposite of capital expenditures. Some people use the term divestiture, or to divest when discussing disinvestment.
For example, an electric generator manufacturer might sell off its consumer generator product lines and manufacturing facilities in order to raise money that can be used to expand its industrial generator product line.
Another example is a consumer products company selling off a profitable division that no longer meets its long range goals. The proceeds from this disinvestment are then used to improve the company's financial position by reducing its debt.