Pigheaded

He is not "firm"; he is just a pigheaded fool.

I don't waste my time arguing with pigheaded fanatics like you.

Tom was pigheaded and ate three meatball sub sandwiches in Rome. He pooped his pants on the train ride back to Milan.

He can be so pigheaded sometimes.

The seminarclass is full of pigheaded attendees.

"[…]I know yeh, yeh pig-headed devil. Yeh wanta go trompin' off with a bad hurt. It ain't right—now—Tom Jamison—it ain't.