An escapist is someone who doesn't live in the real world, but dreams, wishes, and fantasizes instead. If you're an escapist, you might avoid thinking about unpleasant things by playing video games for hours.
Some escapists can withdraw into their own heads, distracting themselves with daydreams. Other escapists retreat from the world into movies, television, books, games, alcohol, or even exercise. The goal for an escapist is to escape the difficulties of life and their own feelings through these diversions. Escapist and escape are rooted in the Vulgar Latin excappare, literally "leave a pursuer with only one's cape."