I. gəˈrü, ˈgu̇(ˌ)rü, ˈgü(- noun
( -s )
Etymology: Hindi gurū, from Sanskrit guru, literally, heavy, weighty, venerable — more at grieve
1.
a. : a personal religious teacher and spiritual guide in Hinduism
b. often capitalized : one of a line of ten chief spiritual leaders in Sikhism recognized within the Sikh community as personal exemplars and temporal leaders as well beginning with Guru Nanak (1469-1538) and ending in 1708 with the death of Guru Govind Singh
2. : a person who acts as one's teacher and guide in matters of fundamental intellectual concern
seeking the clique or the guru essential to his soul — John Masefield
II. noun
1. : one who is an acknowledged leader or a chief proponent
2. : expert