be (as) stubborn as a mule

To be very devoted to a particular opinion or course of action, especially when faced with opposition. My toddler is as stubborn as a mule and has a tantrum every night at bedtime because he doesn't want to stop playing. You'll never get Rich to change his opinion—he's stubborn as a mule.

Common Names:

Name	Pronounced	Usage
Yehoyakim	-	Biblical Hebrew
Lagina	-	African American (Rare)
Lemuel	['lemjuəl]
Merrill	['merəl]
Seo-Yun	su-yoon	Korean
Angelos	-	Greek