The compound adjective "water-soaked" is a transparent combination of two deeply rooted English elements. "Water" originates from the Proto-Indo-European wódr̥, a neuter noun that is the source for water terms across many Indo-European languages, from Greek hydor to Russian voda. "Soaked" derives from the Old English verb sōcian, meaning to become saturated or steeped in liquid, likely from a Proto-Germanic root related to suction or moisture. The compound's logic is perfectly literal: it describes the state (soaked) caused by the specific agent (water), directly following the Germanic pattern of creating descriptive adjectives by combining a noun with a participle. This construction efficiently specifies the type of saturation, distinguishing it from being soaked in other liquids.

Structure: water (liquid) + soaked (saturated) - water: From Old English wæter, of Proto-Germanic origin; related to Dutch water and German Wasser. The core noun denoting the clear, liquid substance. - soaked: The past participle form of the verb soak, from Old English sōcian ("to become saturated"), of Proto-Germanic origin. Functions as an adjective-forming element indicating a state or condition resulting from the action of the verb.