intractable

intractable    [in-Trak-tuh-buh l]

adjective. difficult to manage or control 

"The World Bank's mission is to tackle the three intractable challenges facing the world:  The first is ending extreme poverty. The second is preparing for the next pandemic. And the third is battling climate change."

"The homeless population in Los Angeles is at 44,359. The number has spiked 12% in two years, cementing Los Angeles' reputation of having the most intractable homeless problem in the nation."

"Greece bailout talks: an intractable crisis with three possible outcome. Greece can either exit the eurozone, surrender to EU's demands and more austerity, or play for more time."

http://www.vocabulary.com/dictionary/intractable?family=Intractable