past prime

past (someone's or something's) prime

No longer in an ideal state or condition. Many gymnasts are past their prime when they are only teenagers. This computer is so slow that it's definitely past its prime.See also: past, prime

past someone's (or something's) prime

Fig. beyond the most useful or productive period. Joan was a wonderful singer, but she's past her prime now. This old car's past its prime. I'll need to get a new one.See also: past, prime