(1) (physics) (chemistry) Lacking an affinity for water; insoluble in water; repelling water.
(2) Of, or having hydrophobia (literally, the fear of or water).
Examples of hydrophobic molecules include the alkanes, oils, fats, and greasy substances in general.
Word origin: Attic Greek hydro- for water and phobos for fear.
Related forms: hydrophobicity (noun), hydrophobe (noun).