Jsson Hickel defines it as basically climate justice but for reducing energy use and resource use in production. Ways to reduce energy use include making fewer things or not making unnecessary things, which goes against capitalist growth tendencies, so the name kind of fits. Confusingly, GDP could go up under a "degrowth" of this type.

In my opinion the countries with the political capacity to reduce energy and resource use would fail to actually do do if they basically crashed their economies via lower GDPs that only they take on. It might look good for the world for a few months or years but eventually they'd need to reverse course either due to political pressure or because it becomes a failed state. Realistically, countries will need GDP growth to coincidd with reduced energy use. China is going in the right direction for this by developing production for things like solar and wind and addressing energy efficiency and pollution at its factories. Both are massive challenges that have not been fully overcome by a long shot, but they show how degrowth depends on improvements in production and its forces to be vianle.