Spirit
The words are derived from respiration, and accordingly, if you consider the words themselves, they belong first of all to creatures; yet if you consider the thing signified by them, they belong first of all to the Creator, and especially to the Holy Spirit. The words principally denote a complete immaterial substance, in which God exists principally, and they apply by analogy to creatures.
Petrus van Mastricht. Theoretical-Practical Theology: The Works of God and the Fall of Man, ed. Joel R. Beeke, trans. Todd Rester, vol. 3 (Grand Rapids, MI: Reformation Heritage Books, 2023), 306