Sanyasa (pronounced sanyaas) symbolises the conception of the mystic life in Hinduism where a person is now integrated into the spiritual world after wholly giving up material life. One who walks this path is known as a sannyasi, sannyasin or sanyasi. The sanyasi lives without possessions, practices yoga meditation and prays to his/her conception of God in the hopes of ultimately achieving samadhi (enlightenment) and, subsequently, moksha (liberation).
This is a Sanskrit word. The word "Nyasa" means path. "San" is a prefix that denotes integration. The word sanyasa The person following Sanyasa is called a Sanyasi.
This word is generally used to denote a particular phase of life. In this phase of life, the person develops Vairagya or a state of determination and disillusionment with material life. He thus renunciates all worldly thoughts and desires, and spends the rest of his life in spiritual contemplation. It is the last in the four phases of a man, namely, Brahmacharya, Grihastha, Vanaprastha, and finally Sanyasa, as prescribed by Manusmriti for the Dhwija castes, in the Hindu system of life.
Orthodox Hindus will generally not accept the claims of the followers of Osho/Bhagwan/Rajneesh to be sannyasins and may even find this claim insulting.
Having succeeded in overcoming all sensual affections and desires, and in acquiring perfect equanimity towards everything around him, the hermit has fitted himself for the final and most exalted order, that of devotee or religious mendicant.
As such he has no further need of either mortifications or religious observances; but with the sacrificial fires reposited in his mind, he may devote the remainder of his days to meditating on the divinity. Taking up his abode at the foot of a tree in total solitude, with no companion but his own soul (jiva), clad in a coarse garment, he should carefully avoid injuring any creature or giving offence to any human being that may happen to come near him. Once a day, in the evening, when the charcoal fire is extinguished and the smoke no longer issues from the fire-places, when the pestle is at rest, when the people have taken their meals and the dishes are removed, he should go near the habitations of men, in order to beg what little food may suffice to sustain his feeble frame. Ever pure of mind he should thus bide his time, as a servant expects his wages, wishing neither for death nor for life, until at last his soul is freed from its fetters and absorbed in the eternal spirit, the impersonal self-existent Brahman.