What is the Biblical definition of “Fornication”?

The word fornication is a blanket term for illicit sexual intercourse in all its various forms. Adultery is fornication in a married state (Cyclopedia of Biblical, Theological, and Ecclesiastical Literature). These are sins as defined in the seventh commandment (Ex. 20:14 and 1Cor. 6:18-20). Fornication comes from five separate words in the Bible, two from the Hebrew and three from the Greek (zanah, taznuwth, porneia, porneuo, ekporneuo). These words all share similar connotations. They can mean illicit sexual relations between two unmarried persons. They can also mean adultery, whoredom, or a spiritual act of unfaithfulness in worship of Yahweh, as Israel committed being the betrothed of Yahweh.

The first time the word fornication is used in the Old Testament is in 2Chronicles 21:11. It is from the Hebrew Zanah (No. 2181 in Strong’s Exhaustive Concordance Hebrew and Chaldee Dictionary) and usually refers to prostitution. It is also defined in Strong’s as to commit adultery (usually of the female, and less often of simple fornication, rarely of involuntary ravishment); zanah is used most frequently to signify spiritual prostitution or idolatry in worship.

The Complete Word Study Old Testament offers a more precise definition of fornication than Strong’s. It notes on p. 2312 in its Lexical Aid, “To fornicate, commit fornication, be a harlot, play the harlot, commit adultery; to apostatize, have intercourse with false g-ds or foreigners; to seduce. The main idea is to commit illicit sexual intercourse, particularly with women. However, this strong image is used in a figurative sense to describe illegal contact between Israel and other nations and their g-ds…”

*The second word translated fornication in the English is found once, in Ezekiel 16:29. It is the Hebrew taznuth (No. 8457) and means harlotry, idolatry.

*The third word translated fornication is the Greek porneia (No. 4202) and is first used in Matthew 5:32. It is defined in Strong’s as “from 4203; harlotry (incl. adultery and incest); fig. Idolatry: – fornication.” Porneia is used 32 times in the New Testament. The word fornication in Matthew 5:32 is often taken to denote an act of adultery, however an in-depth study will prove this understanding false, and confirm the true usage of this Greek word “porneia” in this particular passage, which is fornication, pre-material sex (RSB note). The Scriptures consider the betrothal or engagement period a virtual marriage (note that Joseph wanted to divorce Mary even though they were only betrothed, Matt. 1:19).

*The Greek porneuo is the fourth word translated fornication. It means to act the harlot and indulge in unlawful lust of either sex, or to practice idolatry.

*The fifth word translated fornication is the Greek ekporneuo and means to be utterly unchaste and implies excessive indulgence in illicit sex (Jude 7). It is porneuo on steroids.

In the fifth chapter of 1Corinthians Paul admonishes the Corinthian assembly to remove the sin that they were allowing in the assembly. One of the sins listed by the Apostle was a gentile committing “fornication” with his father’s wife. Now this is not what we consider fornication, but more accurately signifies incest with his stepmother.

In summation, fornication in either the Hebrew or Greek can have a wide range of definitions. It can mean literal fornication, adultery, harlotry, incest, pedophilia, bestiality, or any other sexual restriction that Yahweh has placed on mankind.