hydrophobicPronunciation: /hʌɪdrə(ʊ)ˈfəʊbɪk/Definition of hydrophobic adjective 1tending to repel or fail to mix with water. The opposite of hydrophilic. 2of or suffering from hydrophobia. Derivatives hydrophobicity noun hydrophobic in other Oxford dictionaries Definition of hydrophobic in the US English dictionary