Desolate means to lay waste, to make uninhabitable: “They were afraid the severe storm would lead to a desolate gathering for the open air party.”
As an adjective it means lonely, solitary; uninhabited, deserted: “The story of the desolate castle in the wilderness intrigued the explorers.”
Dissolute means immoral, debauched: “Generally, dissolute men are charming individuals.”
2. A description of someone whose way of living is considered morally wrong: “It’s sad to say, but she has led a dissolute life as a prostitute ever since she left home as a teenager.”
The dissolute army officer marched his army through the countryside, planning to desolate it for future farming.
By the time his army reached the sea, a whole swath of country side wasdesolate and uninhabitable.