Why do some people have a 'proclivity' for violence? [=why are some people violent?]
He shows no 'proclivity' towards aggression. [=he is not aggressive]
She has a 'proclivity' [='tendency'] to assume the worst.
(..) But how on earth are we gonna do that? Why don't you confer with Mr. Finnigan? As I recall, he has a particular proclivity for pyro-technics. I can bring it down. That's the spirit! Away, you go. You do realize, of course, we can't keep out You-Know-Who indefinitely. (..)2011 Harry Potter and the Deathly Hallows: Part 2