A sadhu (m.) or sadhvini (f.) is a spiritual seeker who has renounced the world and its attachments. This ascetic or yogi gives up the three householder aims of life—kama, artha, and dharma, and turns the rest of life toward moksha. In India they live in ashrams, caves, forests, and temples, or wander.
Within the International Nath Order that life is honored and not offered. Shri Gurudev Mahendranath was himself a sadhu and the last guru of the Adinath and Uttara Kaula sadhu seats. He would not give sannyas diksha in the West: no marriage, no employment, no property. The initiation of this Order is a householder transmission. A Nath or Devi may work, marry, and keep a home. That is the point of the Order, not a lapse from it. Do not read Sadhu as another word for Nath. Nath here names the initiate of a householder stream.