toughie

noun3

1. •
   (informal) Something that is tough, or difficult.

   • His question is a toughie. I might have to do some more research.
2. •
   A tough; Someone or something that acts as a thug or bully.

   • The liberal states, in the present situation, are the "softies"; the Fascist states are the "toughies". And the toughies are always able to get away with "murder" until the softies become tough. — 1936
3. •
   Someone or something that is strong and resilient.

   • Sansevieria and aspidistra are two old houseplant toughies that make good indoor choices. — 1977