1.manage or deal with (something) wrongly or ineffectively. 2.manipulate roughly or carelessly. for example "the officer had messed up (mishandled) the situation" hope fully helped.

It's a slang expression and depends on the situation, but generally means "That's crazy / bad / unfair." For example: A: "My professor is a jerk! He says we have to write a research paper during winter vacation." B: "What? Seriously? That's just messed up." A: "I know. It's not fair. All the other students get to relax."