Usually written out as Distributed Denial of Service, this attack strategy aims at making a server incapable of serving by flooding it with waves of requests coming from a whole network of so-called bots. These are computers that have been hacked, and are commanded to operate in this manner without the actual user of the system being aware of it.
In the meaning of the Acrosstic above, it is more a matter of several bad actors operating together to achieve some illegal act. This might be aimed at companies, or at certain wealthier people, since there great results can be gained.