1. General: Measure of prudence, responsibility, and diligence that is expected from, and ordinarily exercised by, a reasonable and prudent person under the circumstances. 
2. Business: Duty of a firm's directors and officers to act prudently in evaluating associated risks in all transactions. 
3. Investing: Duty of the investor to gather necessary information on actual or potential risks ... Read more

USAGE EXAMPLE

When it came to his investments, Ken never put much research into it, but after a huge huge loss, he started to do his due diligence.