A mess is something that's a complete screw up. It could be your extremely preppy and/or tomboyish daughter, that carpet stain on the floor that won't come out even if you bleach it 727.9 times, that time of the month, and many other things at the same time.
Messes can be hard to get rid of and/or clean up. For instance, if your life is in a mess, well, it's pretty hard to unscrew yourself up. So you're pretty much screwed,
Also, if your child takes a bowl of chili and throws it across the kitchen, smashing the bowl against the wall and makes chili go everywhere, that can be hard to clean up, too, and it wasn't even your fault. It was your demonic child who doesn't know what he/she's doing.
There was even a boy with a surname of Mess, and boy was he a mess. His first name was Ima, which is actually a girl's name so people made fun of him.
As time moved on, and the boy grew into a man, people called him a manmade mess, which, in the world's opinion, really is a stupid name and they could've thought of a better one. He lived in a village for all his life, when he could've been hanging out with actor Will Smith or some other awesome thing.
Instead, he had to choose the countryside instead of the city side. Oh well.