A good succinct definition of Degrowth:
“Degrowth is a planned and democratic reduction of production and consumption in rich countries to reduce environmental pressures and inequalities, while improving well-being. It has four main characteristics: sustainability, justice, well-being and democracy. Unlike a recession, degrowth is not accidental and general but chosen and selective. It is a societal project that aims to abandon the race for monetary accumulation in favour of a vision of development centred on social health and ecological resilience.”
(“Degrowth goes more far beyond reduction of GDP”; by Timothée Parrique, in Polytechnique insights.)