The spirit of God; the spirit of the living being, life force. Now also in weakened sense: vitality, liveliness.
Origin
Early 17th century; earliest use found in Nathaniel Baxter (fl. 1569–1611), Church of England clergyman and author. From post-classical Latin ruach or its etymon Hebrew rūăḥ breath, wind, spirit, spirit of the living being, (specifically) spirit of God.