Which word means "pertaining to an abnormal fear of water?"

The term that means "pertaining to an abnormal fear of water" is "hydrophobic." In the context of fear-related terminology, "hydrophobic" arises from the root "hydro," meaning water, and the suffix "-phobic," which indicates fear or aversion. Thus, when combined, it specifically describes a person who has an irrational fear of water.

Other terms presented in the choices may seem related but do not define the specific phobia associated with water. "Hydrophonic," for instance, might relate to sound or movement in water but does not pertain to fear. Likewise, "hydrophonia" does not accurately convey the concept of fear, and "hydraphobia" seems like a misspelling and does not have recognized usage in medical terminology. Hence, "hydrophobic" is distinctly the correct term for this specific abnormal fear.