We cannot call anyone "feisty" a "punk." The dictionary defines "punk" as "a young ruffian; hoodlum." It's not the same as feisty, since feisty can indicate that the person is full of energy and not necessarily in a bad way. For example:
"They have a very feisty child who brings a lot of energy to his basketball team."
This child is not a punk just because he has a lot of energy. He would only be a punk if he picked on another person.
I hope my answer helped. Please let me know if it didn't.