Nai, also known as Sain is a generic term for occupational castes of barbers. The name is said to be derived from the Sanskrit word nāpita (नापित). In modern times Nai in northern India refer to themselves as "Sain" instead of Nai. The Nai caste is classified as an Other Backward Class in most of the state in India. https://en.wikipedia.org/wiki/Nai_(caste)