What color if you mix grey and orange?

The color would literally be called a "grayed orange."

Gray made of white and black doesn't actually change the color itself, it just fades the color out. The color will be duller.

If you use a tinted gray the tint will affect the color. A gray with blue tint is described as blue, but has blue undertones. Mixing this with orange would result in a brownish gray version of the original orange. It would still be predominately described as orange.