1. 中年的
If you describe someone as middle-aged, you mean that they are neither young nor old. People between the ages of 40 and 60 are usually considered to be middle-aged.
e.g. His sisters are grown up and his parents are middle-aged.
他的姐妹们都已成人，而他的父母亲也人到中年。
e.g. ...middleaged, married businessmen.
已婚的中年商人
2. 具有中年人特点的;保守的;过时的
If you describe someone's activities or interests as middle-aged, you are critical of them because you think they are typical of a middle-aged person, for example by being conventional or old-fashioned.
e.g. Her novels are middle-aged and boring.
她的小说刻板乏味。