Webster's Revised Unabridged Dictionary · 1913

Gooroo

Gooroo (go*ro") , noun

[Hind. gurū a spiritual parent or teacher, Sanskrit guru heavy, noble, venerable, teacher. Compare Grief.]

1.
A spiritual teacher, guide, or confessor among the Hindus; a guru. — Malcom
2.
one who has expert knowledge of a technical area and serves as an advisor to others; an expert and teacher. Usually written guru.
3.
an intellectual or spiritual guide or advisor; a mentor. Usually written guru.

Also: Guru