investor. A person who buys an asset with the expectation that its market value will increase and yield a profit when sold. A person whose investment strategy focuses on the long-term, rather than speculation about short-term market movements. Compare to Daytrader; scalper. person who buys an asset with the expectation that its market value will increase and yield a profit when sold. A person whose investment strategy focuses on the long-term, rather than speculation about short-term market movements.