The Greek word Χριστιανός, transliterated into English as Christianós, is derived from the Greek word Χριστός, transliterated into English as Christós, an adjective meaning “anointed,” which is often used in the Greek New Testament as a substantive meaning “anointed one.”
If Χριστός means “anointed (one),” what does Χριστιανός mean? The answer lies in the suffix -ανός which is actually the Greacized transliteration and equivalent of the Latin suffix -anus.
In Studies in Jewish and Christian History: Part Three, Elias Joseph Bickerman wrote,1
All these Greek terms, formed with the Latin suffix -ianus, exactly as the Latin words of the same derivation, express the idea that the men or things referred to, belong to the person to whose name the suffix is added. In Greek as in Latin the suffix -ianus is a substitute for the possessive genitive... The term Καισαριανοί corresponds to the ellipse Καίσαρος (Caesaris servus [“a slave of Caesar”]) in other documents. The “Christians” belong to Christ, they are οί τοῦ χριστοῦ [“those of Christ”] as Paul says.
For example, according to Lewis and Short, the Latin word Augustanus means “Of or belonging to an emperor.” Likewise, Christianus, the Latin equivalent of the Greek word Χριστιανός, means “Of or belonging to Christ.”
Christians are “those of Christ” (οἱ τοῦ Χριστοῦ) (i.e., “Christ’s);2 they belong to Christ, as his possessions, because Christians are “slaves of Jesus Christ” (δοῦλοι Ἰησοῦ Χριστοῦ).3 Of course, this is why Jesus Christ is known as our “lord,” or Greek κύριος, literally “master” (as in slave-master). Therefore, the words Christianus and Χριστιανός imply slavery. For this reason, these words were applied to Christians by non-Christians as a derogatory epithet, for the condition of servitude (slavery) was ignominious. However, believers in Christ cherished the epithet because it was a honor to be slaves of Christ, unlike other masters.
Bickerman, Elias Joseph. Studies in Jewish and Christian History: Part Three. Leiden: Brill, 1986.4
1 p. 147
2 Gal. 5:24
3 Phil. 1:1
4 For original publication, see: Bickerman, Elias Joseph. “The Name of Christians.” Harvard Theological Review, 42.2: 1949 (109-124).