🔼The name Koa in the Bible
The name Koa occurs only once in the Bible. It's the name of a town of which YHWH aroused the people against Oholibah (= Jerusalem) together with the Chaldeans, Pekod, Shoa and all the Assyrians (Ezekiel 23:23).
🔼Etymology of the name Koa
The name Koa should be expected to come from Assyrian but it's not immediately clear what it might have originally meant. A randomly selected transliterated Assyrian text lights up like a Christmas tree when Googled for "sutu" or "kutu". It appears that the sound of the "u" was greatly favored among Assyrians.
A randomly selected and highly creative Scripture theorist such as your truly, on the other hand, might first of all wonder why Ezekiel reflected the Assyrian name Sutu and Kutu as the semi-monosyllabic Shoa and Koa. Perhaps to make a point? There's nothing in the Hebrew scriptures that resembles קוע (Koa), but perhaps Ezekiel had the verb or noun קעקע in mind:
A doubling of an element (in this case קע or קוע) usually works diminishing. So if the verb קעקע means to pull or tear down, and the noun קעקע denotes a mark or tattoo, the element קע or קוע must either denote complete bulldozing or a full-body tattoo. Probably the former.
None of the sources we commonly consult (or any other one we looked at) dares to propose a meaning of the name Koa. Whatever it may have meant in its original language is a mystery, but to a Hebrew audience it may have meant Razing or Leveling.