This is the 7839th most frequent Chinese word.
随身
"随身" means "to carry along" or "on one's person."
Here, "随身" means "with oneself," describing the act of carrying something close and available for use.
我总是随身携带一支笔。
I always carry a pen with me.
In this sentence, "随身" serves as an attributive adjective to specify items that are kept close to oneself.
随身的物品很重要，要妥善保管。
Items carried with you are important and need proper safekeeping.
"随身" is used here to indicate that the item being carried, the book, is physically kept with the person as they travel.