Catch up Definition 1 of 4Pro Tip 1/3Progress Focus Used when emphasizing the effort to reach a current standard or level. After her vacation, she had to catch up with the rest of the class. Pro Tip 2/3After Absence Often used when returning to work or school after a break. He's been out sick, but he'll catch up quickly. Pro Tip 3/3Not Instant Implies a process or period of effort, not an immediate change. I'm behind on my reading, but I'll catch up over the weekend.