Sannyasa is the life stage of renunciation within the Hindu philosophy of four age-based life stages known as ashrams, with the first three being Brahmacharya (bachelor student), Grihastha (householder) and Vanaprastha (forest dweller, retired).Sannyasa is traditionally conceptualized for men or women in late years of their life, but young Brahmacharis have had the choice to skip householder and retirement stage, renounce worldly and materialistic pursuits and dedicate their lives to spiritual pursuits (moksha).
Sannyasa is a form of asceticism, is marked by renunciation of material desires and prejudices, represented by a state of disinterest and detachment from material life, and has the purpose of spending one's life in peaceful, love-inspired, simple spiritual life.
The meaning of sannyasa is sacrificing oneself for the sake of something. Sannyasa means dedication; it does not mean renunciation. In the dictionary, the meaning of sannyasa is not tyaga, renunciation; it means samarpan, surrender. It means trust. Nyasa means to place yourself in a trust. If you allocate a certain amount of your money to help the poor, you have placed it in trust; it has been dedicated.
One does not take sannyasa for the sake of attaining God. The aim of sannyasa is not moksha. The only aim of sannyasa is seva, selfless service. Sannyasa is such a life in which one cannot be a slave to circumstances.