ghost ship
The most well known ghost ship (as the term was previously used) was The Flying Dutchman, but these days a ghost ship is a vessel that is avoiding being identified and held accountable for violations of sanctions or violations of national borders, either by flying a flag of convenience of a country that is not caught up in current sanctions, or by turning off its GPS tracker referred to as the Automatic Identification System (AIS) or by changing names frequently or obscuring ownership or, as in the case of oil tankers, making ship-to-ship transfers in international waters.
This has particular significance in the light of Russia’s efforts to sell its oil to fund the war in Ukraine.