He's '(as) stubborn as a mule'. [=he's very/extremely stubborn]
She 'has a stubborn streak'. [=she is often stubborn]
She's wrong, but she's too 'stubborn' to admit it.
(..) Your record was too good to just walk away. Maybe I got greedy. Harvey. I'm not testifying. You're being stubborn. And this isn't one where you get to make the call. I'm sorry. I've done all I can. It wasn't just his cases (..)2011 TvShow: Suits Title: Rules of the Game Season: 1 Episode 11