Well-being has many competing definitions, none of them universal, most of them correlated to happiness, all of them correlated to assumptions about wealth and "who is a well being" in a number of senses.

In welfare economics and classical economics it is usually equated to quality of life, though that latter term is far more closely defined, e.g. the UN QOL measure.

In neoclassical economics it is assumed to be largely determined by the standard of living: the amount of money and access to goods and services that a person has;

Arguments in green economics tend to link it more to:

quality of life, value creation, value reporting, Genuine Progress Indicator, Gross National Happiness, Gross Domestic Product, Canada Well-Being Measurement Act, triple bottom line, full cost accounting, natural capital, and economic philosophy.