Chuffed...

Some years ago, a friend living across the pond used the word "chuffed" to express a great feeling about himself.

Up to that point, I had never heard this word, and since I've used it to describe a face Max makes.

There are times where saying Max is chuffed is the only way to describe his mood. He gets especially puffed up and pleased with something he's accomplished. He's genuinely quite pleased with himself.