Well-being, or wellbeing, also known as wellness, prudential value, prosperity or quality of life, refers to what is intrinsically valuable relative to someone. So the well-being of a person is what is ultimately good for this person, what is in the self-interest of this person. Well-being can refer to both positive and negative well-being. In its positive sense, it is sometimes contrasted with ill-being as its opposite. The term "subjective well-being" denotes how people experience and evaluate their lives, usually measured in relation to self-reported well-being obtained through questionnaires.
Well-being has been treated as a variable from none to a high degree of well-being. This usage of well-being has in later times been widened to also include a negative aspect. With the aim of understanding how different route environmental variables affect the wellbeing during walking or cycling, the term "environmental unwellbeing" has been coined.
Different forms of well-being, such as mental, physical, economic, or emotional are often closely interlinked. For example, improved physical well-being (e.g., by reducing or ceasing an addiction) is associated with improved emotional well-being. As for another example, better economic well-being (e.g., possessing more wealth) tends to be associated with better emotional well-being even in adverse situations such as the COVID-19 pandemic. Well-being plays a central role in ethics since what a person ought to do depends, at least to some degree, on what would make someone's life get better or worse. According to welfarism, there are no other values besides well-being.
The terms well-being, pleasure, and happiness are used in overlapping ways in everyday language, but their meanings tend to come apart in technical contexts like philosophy or psychology. Pleasure refers to experience that feels good and is usually seen as one constituent of well-being. But there may be other factors, such as health, virtue, knowledge or the fulfillment of desires.