1. lacking affinity for water; tending to repel and not absorb water; tending not to dissolve in or mix with or be wetted by water (Freq. 2) • Ant: hydrophilic • Derivationally related forms: hydrophobicity • Topics: chemistry, chemical science 2. abnormally afraid of water • Syn: aquaphobic • Similar to: afraid • Derivationally related forms: aquaphobia (for: aquaphobic)