Tough Cookie Meaning

Example : 1973, "Ioannidis: Power in the Wings," Time, 10 December 1973:  An austere, hard-lining rightist, who lives alone, Ioannidis is described by one Washington military official as "a real tough cookie."2002, Picabo Street (with Dana White), Picabo: Nothing to Hide, Contemporary Books (2002), ISBN 007140273X, page 6:  I run to Micki and give her a hug. She was racing with a broken thumb — a tough cookie, just like me.2005, Liz Austin, "Miers had stormy tenure at Texas Lottery Commision," Spokesman-Review, 3 October 2005:  "Although she's a small-framed woman, we all believed she came through the Marines and maybe ate nails for breakfast because she's one tough cookie," said Horace Taylor […]2001, Sybille Engels, Basic Gardening: Everything You Need to Make Your Garden Grow, Silverback Books (2001), ISBN 9781930603769, page 134:  Boxwood is a pretty tough cookie. Wind, cold, wet, exhaust fumes, and industrial pollution are of no consequence.2006, "Katrina Cat", Jet, 13 March 2006  Though its name is Cupcake, Tristan Carter's cat proved it was one tough cookie surviving on its own since Hurricane Katrina forced Carter to abandon it […]2002, Encyclopedia of North American Sporting Dogs (ed. Steven Smith), Willow Creek Press (2002), ISBN 1572235012, page 63:  The pup that struggles constantly might be one tough cookie when it comes to training; […]