Money laundering refers to disguising illegally obtained money to make it appear legitimate. It involves three steps - placement, layering, and integration. Criminals like drug dealers, mobsters, corrupt politicians, and terrorists engage in money laundering to hide the source and destination of funds from illegal activities. Key causes of money laundering include tax evasion, increasing profits from crime, and limited risks of exposure. Money laundering distorts economies, increases corruption and crime, undermines financial market integrity, and risks countries' reputations.