tough cookies

Noun

tough cookie (plural tough cookies)

1. (informal) A person who can endure physical or mental hardship; a hardened, strong-willed person.
   • An austere, hard-lining rightist, who lives alone, Ioannidis is described by one Washington military official as "a real tough cookie."1973 December 10, “Ioannidis: Power in the Wings”, in Time

   Synonyms:

   survivor, trooper

2. (informal) A hardy, resilient animal or plant.
   • Boxwood is a pretty tough cookie. Wind, cold, wet, exhaust fumes, and industrial pollution are of no consequence.2001, Sybille Engels, Basic Gardening: Everything You Need to Make Your Garden Grow, Silverback Books, →ISBN, page 134
3. (informal) Something troublesome or difficult to handle.
   • The pup that struggles constantly might be one tough cookie when it comes to training; […]2002, Steven Smith, editor, Encyclopedia of North American Sporting Dogs, Willow Creek Press, →ISBN, page 63