Here are some other related words that you might find useful:
* "Nieugięty" - This word means "unyielding" or "unbending", which can be another way to describe someone who is stubborn.
* "Uporczywy" - This word means "persistent" or "insistent", which can be used to describe someone who is stubborn about a particular thing.
* "Główny" - This word means "headstrong" or "obstinate", and implies a strong will that is difficult to change.
The best word to use will depend on the context and the specific nuance you want to convey.