What money laundering actually is

Money laundering is the process of making money obtained through criminal activity appear to have come from a legitimate source. The underlying crime that generated the money, drug trafficking, fraud, corruption, tax evasion, and so on, is called the "predicate offence." Laundering is a separate offence from whatever generated the money in the first place.

The goal, from the launderer's perspective, is simple: get criminal proceeds into the financial system, move them around enough to obscure where they really came from, and end up with money that looks clean and can be spent or invested openly.