Mark did not believe in soul/spirit, so this concept is only an analogue of the LP concept of Disconnection. However, the concept does indicate Marx was thinking about disconnection and the dissatisfaction of needs.
Marxist alienation is loss of control, or powerlessness. Under The System, we lose control of what we do, how we work, and the products of this work. We also become disconnected from each other, our families and communities. We also become disconnected from our Species Being. As loss of control, alienation can be seen primarly as a failure to satisfy our Essential Needs for Esteem/Power. Alignment, and so on. In order to maintain itself, Captitalism diminishes the worker and removes from them all control of their life, their work, their product, and so forth.