Alienation is a term used to describe a feeling of disconnection or separation from a group, whether it be friends, family, or wider society, to which an individual has an affinity. The term has been used over the ages with varied and sometimes contradictory meanings. In ancient history, it could mean a metaphysical sense of achieving a higher state of contemplation, ecstasy, or union, becoming alienated from a limited existence in the world, in a positive sense. In a broader philosophical context, especially in existentialism and phenomenology, alienation describes the inadequacy of the human being (or the mind) in relation to the world. The human mind (as the subject who perceives) sees the world as an object of perception and is distanced from the world, rather than living within it.

Alienation is most often represented in literature as the psychological isolation of an individual from society or community. For example, Shakespeares Hamlet is described as the supreme literary portrait of alienation. In social sciences, alienation is the state of feeling estranged or separated from ones milieu, work, products of work, or self. Marx spoke of alienated labor under capitalism, where work was compelled rather than spontaneous and creative, workers had little control over the work process, the product of labor was expropriated by others to be used against the worker, and the worker himself became a commodity in the labor market. Alienation consisted of the fact that workers did not gain fulfillment from work.

Alienation can also refer to the process of a property owner voluntarily giving or selling the title of their property to another party. When property is considered alienable, that means the property is able to be sold or transferred to another party without restriction. Some properties may be subject to a restraint on alienation, which can prohibit the property owner from transferring or selling the property to another party.