spring chicken

plural spring chickens

1. cookingA chicken for eating while it is still young.
2. informalA person who is still young.

   You know the world. You are no spring chicken.

   1908, Upton Sinclair, chapter 5, in The Money Changers

   3 more examples

   A real candidate arose to challenge dapper Robert Rice ("Buncombe Bob") Reynolds, aging coxcomb of the Senate. The candidate, no spring chicken himself: tall, lean Clyde Roark Hoey (pronounced Hooey), 65, one of the most popular Governors the state ever had.

   1943 May 10, “The Pot Boils”, in Time

   He doubtless hoped for a sympathetic ruling from President Reagan, at 70 no spring chicken himself.

   1981 November 23, “Newest Sub, Oldest Sailor”, in Time

   It is a special day for you indeed, for both of us, bodies incorporeal, receptive always to life's joys appreciative in any way I can, you like to remind me were both getting old; I'd remind you that, at fifty-five, you're still a spring chicken.

   2014, William Friedman, Hearts and Minds, page 64