Leisure has often been defined as a quality of experience or as free time. Free time is time spent away from business, work, job hunting, domestic chores, and education, as well as necessary activities such as eating and sleeping. Leisure as an experience usually emphasizes dimensions of perceived freedom and choice. It is done for "its own sake", for the quality of experience and involvement. Other classic definitions include Thorstein Veblen's (1899) of "nonproductive consumption of time." Free time is not easy to define due to the multiplicity of approaches used to determine its essence. Different disciplines have definitions reflecting their common issues: for example, sociology on social forces and contexts and psychology as mental and emotional states and conditions. From a research perspective, these approaches have an advantage of being quantifiable and comparable over time and place.

Leisure studies and sociology of leisure are the academic disciplines concerned with the study and analysis of leisure. Recreation differs from leisure in that it is a purposeful activity that includes the experience of leisure in activity contexts. Economists consider that leisure times are valuable to a person like wages that they could earn for the same time spend towards the activity. If it were not, people would have worked instead of taking leisure. However, the distinction between leisure and unavoidable activities is not a rigidly defined one, e.g. people sometimes do work-oriented tasks for pleasure as well as for long-term utility. A related concept is social leisure, which involves leisurely activities in social settings, such as extracurricular activities, e.g. sports, clubs. Another related concept is that of family leisure. Relationships with others is usually a major factor in both satisfaction and choice.

The concept of leisure as a human right was realised in article 24 of the Universal Declaration of Human Rights.