Dielectric Withstanding Voltage (DWV) is the attribute that defines the high voltage limit for a device under evaluation, whether it is a connector, socket, cable or cable assembly.
DWV is just a simple measure of the voltage that the dielectric material in conjunction with the conductive material can withstand while the device still functions as specified within the application.
Normally, at voltages not exceeding the DWV rating, there would be no arcing, corona, leakage current, etc. that would be detrimental to the Device under Test or the application in which it is being used.
Please note that DWV is only a testing voltage applied. It is not the same as the working voltage. You can consider DWV to be an ‘Absolute Maximum’ type of specification.