The crossword solution for the term REALLY GO is SPEED. SPEED is a measure of how quickly something moves or happens. It is usually measured in units such as miles per hour, kilometers per hour, or meters per second. SPEED is an important factor in many activities, such as driving, running, and sports. It is also used to measure the performance of machines, such as computers and cars. SPEED is often used to describe how quickly someone or something is able to accomplish a task.