A meanie is an unkind person — someone who will not share, who says a hurtful thing, or who spoils the game on purpose. It is a children's word, the sort you hear on the playground, in picture books, and from a parent bending down to a small child: don't be a meanie. The sting is real, but the word itself is soft and small; it does not land as heavily as cruel or nasty. Grown-ups sometimes say it too, though actually then it is half a joke, the way you tease a friend. One more messy truth: English mean also covers a person who will not spend or give, so a child calling someone a meanie may be talking about unkindness or about being stingy, and in the playground those two often feel like the same crime.