“defames.” See commentary on Mark 3:28.
“the Holy Spirit.” “The Holy Spirit” is the name for God that emphasizes His power in operation and His special holiness. God is called “the Holy Spirit” in a number of verses in the NT, including Matthew 1:20; 12:32; and Hebrews 9:8.
[For more information on the uses of “Holy Spirit”, see Appendix 6: “Usages of ‘Spirit.’”]
“will never be forgiven.” For more information on the “unforgivable sin,” see commentary on Matthew 12:31.
“an everlasting sin.” That is, a sin that will not be forgiven but will have everlasting consequences.