🔼The name Sepharvaim in the Bible
There's only once city with the name Sepharvaim in the Bible. It's one of the cities from which the king of Assyria brought people to inhabit the cities of Samaria to replace the exiled people of Israel (2 Kings 17:24).
We don't exactly know where this city may have been located, but according to Rabshakeh, the spokesman of the king of Assyria, it was one of the cities whose god(s) could not protect it against invasion (2 Kings 18:34, Isaiah 36:19), and whose kings were never to be seen again (2 Kings 19:13, Isaiah 37:13).
Once settled in Israel, these foreign nations began to introduce their gods. The Sepharvites were particularly vile, and sacrificed their children by burning them to their deities Adrammelech and Anammelech (2 Kings 17:31).
The ethnonym Sepharvites is spelled the same as the name of their city (ספרוים), and either they or their city was also known as ספרים (Sepharim; 2 Kings 17:31.
🔼Etymology of the name Sepharvaim
The name Sepharvaim is probably foreign, but the way it is spelled clearly reminds of the noun ספר (seper), meaning a writing:
The vaim-part of our name could be construed as a plural form of an extended version of ספר (seper).
Most commentators forgo trying to interpret this name, but to a Hebrew audience it probably would have sounded like Writings of Scribes, or something to that extent.