Any one is selfish who doesn't do what they want.

You're more selfish than I am.
You're the most selfish boy I ever saw." "I'm not!" snapped Colin.

"I'm not as selfish as your fine Dickon is! He keeps you playing in the dirt when he knows I am all by myself.

He's selfish, if you like!" Mary's eyes flashed fire.
"He's nicer than any other boy that ever lived!" she said.

"He's--he's like an angel!" It might sound rather silly to say that but she did not care.
"A nice angel!" Colin sneered ferociously.