What It Means:
Wikipedia: Guru (Devanagari गुरु) is a Sanskrit term for "teacher" or "master", particularly in Indian religions. The Hindu guru-shishya tradition is the oral tradition or religious doctrine or experiential wisdom transmitted from teacher to student. In the United States, the word guru is a newer term, most often used to describe a teacher from the Hindu tradition. In the West some derogatory interpretations of the word have been noted, reflecting certain gurus who have allegedly exploited their followers' naiveté, due to the use of the term in certain new religious movements.
In Hinduism, the importance of finding a guru who can impart vidyā or transcendental knowledge is key. The Bhagavad Gita's premise is the dialogue between God in the form of Krishna and his friend Arjuna, a Kshatriya prince who accepts Krishna as his guru on the battlefield, prior to a large battle. Their relationship is an example of Guru-Shishya or the relationship between a true teacher and his student.
In the Gita, Krishna speaks to Arjuna of the importance of finding a guru:
"Acquire the transcendental knowledge from a Self-realized master by humble reverence, by sincere inquiry, and by service. The wise ones who have realized the Truth will impart the Knowledge to you."
Gurus often live in Ashrams and commit their lives to study and teaching.
In the Upanishads, there are five signs of satguru (true guru):
In the presence of the satguru; Knowledge flourishes (Gyana raksha); Sorrow diminishes (Dukha kshaya); Joy wells up without any reason (Sukha aavirbhava); Abundance dawns (Samriddhi); All talents manifest (Sarva samvardhan).
According to the Advayataraka Upanishad, a true teacher is well-versed in the Vedas, is a devotee of Vishnu, is free from envy, knows yoga and is intent upon it, and always has the nature of yoga.
Urban Dictionary Says:
Guru is a learned man, He shares his knowledge and enlighten all ignorant and works for the mass uplifting of the society by imparting knowledge.
Sree Narayana Guru worked for the uplifting of the downtrodden.
2. Guru: Somebody who is supposed to be an expert on something.
Why do you read advice columns, horoscopes and whatever the fashion gurus and motivational speakers say? You don't need these gurus to govern your life or your point of view. Just be yourself. What do you see? Just be nobody but YOU.