You can download the Windows client and then use one of the following binaries in conjunction with it. Simply extract the zip archive contents to the same directory in which you have placed the Windows install.
It should be noted that the upcoming Mojave release (10.14) arriving on the 24th of September will be the last released to support 32bit applications, so you'll have about another year of being able to utilize the native client on a current macOS install. If you upgrade to 10.15, then this will likely no longer run unless they extend support once more (they already have once), though I see that as unlikely. It was originally distributed as a Universal Binary for PowerPC and Intel, but I've supplied an Intel only copy in case anyone has issues related to that (using TrimTheFat to remove the PowerPC portion).
It is possible that you may have difficulty launching the app how you normally would. If this is the case with you, a workaround is as follows.
World of Warcraft.app.zip
World of Warcraft-IntelOnly.app.zip