I just looked up an interlinear Septuagint and found this.
Hosea 1:1 The word of the Lord which came to Osee the son of Beeri, in the days of Ozias, and Joatham, and Achaz, and Ezekias, kings of Juda, and in the days of Jeroboam son of Joas, king of Israel. 2 The beginning of the word of the Lord by Osee. And the Lord said to Osee, Go, take to thyself a wife of fornication, and children of fornication: for the land will surely go a-whoring in departing from the Lord.
When comparing it to the KJV.
Hosea 1:1,2 The word of the LORD that came unto Hosea, the son of Beeri, in the days of Uzziah, Jotham, Ahaz, and Hezekiah, kings of Judah, and in the days of Jeroboam the son of Joash, king of Israel.
The beginning of the word o f the LORD by Hosea. And the LORD said to Hosea, Go, take unto thee a wife of whoredoms and children of whoredoms: for the land hath committed great whoredom, departing from the LORD.
The same porneia that is translated as fornication in the New Testament, is the same porneia that is translated as whoredom in the Old Testament by the 70 Jewish men who translated the Septuagint from Hebrew into Greek back in 272 BC.