the compound adjective 'water-repellent' is a modern english formation that transparently combines two established elements. the first element, 'water', has a direct lineage from old english and proto-germanic, denoting the ubiquitous liquid. the second, 'repellent', originates from the latin verb 'repellere', meaning 'to drive back', composed of 're-' (back) and 'pellere' (to drive). when combined, the term literally describes a material or substance that 'drives water back', creating a logical and descriptive term for a functional property. this compounding follows a common english pattern for creating technical and everyday adjectives that specify what an object resists.

Structure: water (liquid) + repellent (resisting) water: from old english 'wæter', of proto-germanic origin; the core substance being resisted. repellent: from latin 'repellent-', present participle of 'repellere' (to drive back); functions as an adjective-forming suffix indicating a property of driving away or resisting.