expression, godan verb (-ru)
even a great person declines with age
Proverb meaning that even the most talented or outstanding individual becomes inferior when they grow old, just as a mythical kirin becomes worse than a slow horse.
「麒麟も老いぬれば駑馬に劣る」と言うように、かつての名選手も年には勝てない。
As the saying goes, 'Even a kirin, when old, is inferior to a nag,' even a once-great athlete cannot beat age.