An old person who has the mental or physical characteristics of one who is younger (rare before 20th cent.).
That appears both young and old; especially old in age but having the mental or physical characteristics of one who is younger.
Mid 16th century.
英汉双解词典包含464360条英汉词条，基本涵盖了全部常用单词的翻译及用法，是英语学习的有利工具。