The Holy Spirit v unclean spirits

I've mused before that holiness has more to it than we often credit, more than our irreverent age can easily understand. One thing that we can see is that the Spirit of God is holy, while other spirits are often referred to as "unclean." Is there a sense in which "holy" is the opposite of "unclean"? 

As mentioned, places in the Bible speak of "unclean spirits" on the one side, and the Holy Spirit on the other.

There are places in Paul's letters that use holy as the opposite of unclean, for example: "otherwise your children would be unclean, but now they are holy." (1 Corinthians 7:14)

David prayed, "Create in me a clean heart and renew a right spirit within me." He spoke as if being clean and pure were part of what it means to have a right spirit. 

In some well-known passages of Scripture, the Holy Spirit is associated with baptism. There the Holy Spirit is associated with water -- especially in washing and cleansing.

Holiness starts with making us clean and pure; a clean heart is one of God's great gifts, and an honest person's heart-felt desire.