The art of manifesting to another the fortune (luck), good or bad, that the future has in store for him or her. The real objective in fortune-telling is the disclosure of future events. Quite often, though, to inspire confidence, the fortune-teller will communicate bits of information about a person's past that would be naturally unknown to anyone else. As a presumed help in peering into the world of secret events they employ, for example, tea leaves, a crystal sphere, or a small pool of blood.
The Church considers it gravely wrong to consult a fortune-teller who is known to seriously claim access to the knowledge of future events. It would be a sin of formal co-operation. It is likewise wrong to consult a person who may not actually make such claims, but whom the client believes to be a fortune-teller with powers of divination. The gravity of the sin would depend on how seriously one takes the fortune-teller. If neither party takes the thing seriously and someone has a fortune told as a pastime, there is no sin. But even in this case the danger is that if what was predicted actually takes place, one's faith in fortune-telling is (or may be) aroused and there is danger that what began as amusement may become a temptation to learn about the future through forbidden means.