a profound secret or deep mystery, especially concerning the hidden inner workings of nature or the universe

stealthy and surreptitious in one's actions or movements to avoid being noticed

puzzling and difficult to interpret, especially regarding a person's behavior, expression, or whereabouts

to keep something secret and not make it public; to withhold information

a secret collection or cache of hidden items, often of great value

a treasured rare book

to hand down secret knowledge from generation to generation within a school or family

constipation; the condition of having hard, dry stools that are difficult to pass

strange and secretive; weird and mysterious

to investigate or uncover mysteries or unknown information