My boss has used the word obstreperous several times when referring to one of my employees. Without even knowing what the word actually meant, I could tell (based on my employee’s characteristic) that it meant seriously stubborn.
Merriam-Webster provides 2 definitions for obstreperous:
1 : marked by unruly or aggressive noisiness
2 : stubbornly resistant to control
I’m pretty sure my boss used the second definition of the word for my employee. And the definition is just as I expected. People who are unwilling to yield to authority and relinquish control can be obstreperous.