Meaning

noun a Hindu or Buddhist religious leader and spiritual teacher

noun each of the first ten leaders of the Sikh religion

noun a recognized leader in some field or of some movement

originBorrowed from Hindi गुरु (guru) / Punjabi ਗੁਰੂ (gurū), from Sanskrit गुरु (guru, “venerable, respectable”), originally "heavy" and in this sense cognate to English grieve and, more distantly, brute. Doublet of grave. A traditional, though flawed etymology based on the Advayataraka Upanishad (line 16) describes the syllables gu as “darkness” and ru as “destroyer”, thus ascribing the meaning of…

Etymology from Wiktionary, CC BY-SA 3.0