Both terms are used in regrda to operating a vehicle while impaired by alcohol/illegal drugs. Specifcally, DWI is stands for "driving while intoxicated/impaired" and DUI stands for "driving under the influence". The laws regarding how each is to be treated varies from state-to-state. Additionally, these terms can have different meanings or they can refer to the same offense, depending on the jurisdiction in which a person is were pulled over. In the states where the drunk driving laws are different for a DUI and a DWI, a DUI is treated as a lesser charge and indicates a lesser degree of intoxication than a DWI. Further, these states sometimes may allow the charges of a DWI to be reduced to a DUI.