What a part of "VeloxSwifter" is probably even offensive?

Precisely what it says on the tin. Tried to vary my gamertag to "VeloxSwifter", and it's telling me it's not allowed. It's not too lengthy (precisely 12 characters, I checked), and it isn't taken (In any other case it might simply attempt to append numbers to the tip of it).

I attempted simply Swift, Swifter, and Velox (I might use that however another person has it and I hate the numbers on the tip), it solely appears to be an issue when the 2 are collectively. (e.g. VeloxSwifter, VeloxSwift, SwifterVelox, SwiftVelox)

I’ve completely zero concept what may make this gamertag "not allowed."

What I get when attempting to enter it in