The word spirit has come to mean something pale and shapeless, like an unmade bed. School spirit, the American spirit, the Christmas spirit, the spirit of ’76, the Holy Spirit—each of these points to something you know is supposed to get you to your feet cheering but which you somehow can’t rise to. The adjective spiritual has become downright offensive. If somebody recommends a person as spiritual you tend to avoid him, and usually with good reason. Inspiring is even worse. Inspirational is worse still. Inspirational books are invariably for the birds.
Like its counterparts in Hebrew and Greek, the Latin word spiritus originally meant breath (as in expire, respiratory, etc.), and breath is what you have when you’re alive and don’t have when you’re dead. Thus spirit = breath = life, the aliveness and power of your life, and to speak of a man’s spirit (or soul) is to speak of the power of life that is in him. When the spirit of a man is unusually strong, the life in him unusually alive, he can breathe it out into other lives, become literally in-spiring.
God also has a spirit—is Spirit, says the Apostle John (4:24). Thus God is the power of the power of life itself, has breathed and continues to breathe himself into his creation. In-spires it. (Frederick Buechner, from “Spirit” in Wishful Thinking: A Theological ABC)