hydrophobic Syllabification: (hy·dro·pho·bic)Pronunciation: /ˌhīdrəˈfōbik/Definition of hydrophobic adjective 1tending to repel or fail to mix with water. The opposite of hydrophilic. 2of or suffering from hydrophobia. Derivatives hydrophobicityPronunciation: /-fōˈbisitē/ noun hydrophobic in other Oxford dictionaries Definition of hydrophobic in the British & World English dictionary