Bluish-purple is more blue than purple.
For example:
While recovering from a sprained ankle, John's foot showed an array of deep purple to light pink bruising. Cathy's ankle was more bluish-purple than Trish's ankle, which showed more greenish-yellow bruising.
NOTE: The color of bruises can help determine the time since the bone was broken. Acute breaks often show black to bluish-purple bruising. Older breaks show more diffuse overall coloring, including pinkish-red, greenish-blue, bluish-purple, etc.