Hydro means water, and philic means an attraction or affinity to something.

Hydrophilic substances are molecules that like water. Substances that you can combine with water.

A phobia is an irrational fear.

HydroPHOBIC molecules are things that do NOT like water. These are substances that will not combine with water at all.

Hydrophilic vs. Hydrophobic

For example, oil and water: