In the Hebrew Scriptures, the word most frequently used for "spirit" is ru'ach, meaning "breath; wind; spirit." Having a similar meaning in the Greek Scriptures, the word is pneu'ma.
The way that the Bible uses the term "holy spirit" indicates that it is God's active force that He uses to accomplish a variety of His purposes.
Genesis 1:2 says that "God's active force ["spirit" (Hebrew, ru'ach)] was moving to and fro over the surface of the waters." This shows that God's spirit was his active force working to form the earth.
The Bible says that God's spirit can also supply "power beyond what is normal" to those who serve him. (2 Corinthians 4:7)
It is also recorded that God's spirit empowered the disciples of Jesus to do miraculous things: "Suddenly there occurred from heaven a noise just like that of a rushing stiff breeze, . . . and they all became filled with holy spirit and started to speak with different tongues, just as the spirit was granting them to make utterance." (Acts 2:1-4)
For much more, see
The Holy Spirit—God's Active Force
Is the Holy Spirit a Person?
Is the Holy Spirit really God?