obdurate
stubborn/unyielding hardened against good influeces
Synonyms
inflexible
unshakable
unrelenting
Antonyms
flexible
fluid
submissive
Sentences
1. The outdated, obdurate teacher refused to let go of her tradition of using chalk boards.
2. Often times stories involve a heroic protagonist and an obdurate enemy who the hero eventually overcomes.
The Mr. Men Show - Mr. Rude Vs. Mr. Stubborn