Concise Bible Dictionary:

“New Hazor,” in the south of Judah (Josh. 15:25). In the AV the words are divided, but not in the RV and other translations. It will be seen that Hazor is mentioned again at the end of the verse.

Jackson’s Dictionary of Scripture Proper Names:

enclosure of rejoicing: new enclosure, or possibly "trumpeting of joy: trumpeting anew "