What are gloves that are not five fingers called?

It's called boxing gloves.

Mittens, also known as boxing gloves or mittens, are protective equipment covering hands and fingers, which are mainly used in sports and fitness training to protect hands from injury. Mittens are usually made of leather or synthetic materials and filled with soft fillers, which can provide extra protection and cushioning. Because of its compact design, mittens can effectively prevent fingers and hands from being injured in sports.