A religious student, unmarried, who lives with his spiritual guide, devoted to study and service. Brahmacharya literally means "going after Brahman (Supreme Reality, Self, God)". In Indian religions, it is also a concept with various context-driven meanings.
In one context, Brahmacharya is the first of four Ashrama (age-based stages) of a human life, with Grihastha (householder), Vanaprastha (forest dweller) and Sannyasa (renunciation) being the other three Asramas. Brahmacharya (bachelor student) stage of one's life, up to 25 years of age, was focused on education and included the practice of celibacy. In Indian traditions, it connotes chastity during student stage of life for the purposes of learning from a guru (teacher), and during later stages of life for the purposes of attaining spiritual liberation (moksha).
In another context, Brahmacharya is a virtue, where it means celibacy when unmarried, and fidelity when married. It represents a virtuous lifestyle that also includes simple living, meditation and other behaviors.
Among the Hindu, Jain and Buddhist monastic traditions, Brahmacharya implies, among other things, mandatory renouncing of sex and marriage. It is considered necessary for a monk's spiritual practice. These characteristics mirror the Western notions of the religious life as practiced in monastic settings.
Example via www.ramdass.org: Dealing with Our Stuff