Definition
Alienation, in its tightest sense, is Karl Marx's claim that wage labour under capitalism severs the worker from four things at once: the product they make, the act of making it, their wider human capacities (what Marx called species-being), and from other workers. The condition is not a mood but a structural feature of how production is organised.
In looser modern usage the term names any deep disconnection between a person and the institutions, relationships, or activities that ought to give their life meaning. Sociology, criminology, and psychology each use the word with overlapping but distinct emphases.
Why it matters
How it works
In the Marxist formulation, the worker sells labour-time to a capitalist who owns the product, dictates the process, and pockets the surplus. The worker therefore confronts the product as something foreign, performs the labour as compulsion rather than expression, loses contact with the creative capacities that distinguish humans from animals, and meets fellow workers as competitors rather than collaborators. The mechanism is property and the wage relation, not personal failing.
Later writers stretch the concept beyond the factory. Robert Blauner used it to compare different industries; the Frankfurt School read it through mass culture; criminologists invoke it to explain why some young people invest in delinquent subcultures rather than the labour market they find empty. The risk in this stretching is that alienation comes to mean anything that feels bad — which empties the structural punch Marx intended.