Rhabdomancer is a pretty uncommon word that refers to a person who is able to divine or predict future events by using a stick or rod. If you are looking for synonyms for this word, there are two that most commonly come up - diviner and dowser. A diviner is someone who foretells the future, while a dowser is someone who uses divining rods or wands to locate water or minerals beneath the ground. Both these words are relatively more commonly used than rhabdomancer and are considered easier to understand. That being said, all three words essentially refer to the same thing - the ability to use a tool to predict future events or locate hidden resources.