The term 'waterlog' is a compound formed from two native English words, 'water' and 'log', with its origins firmly in 18th-century nautical jargon. Literally, it described the condition of a ship that had taken on so much water that it became as heavy, sluggish, and unresponsive as a water-soaked log of wood. The 'log' here draws a vivid metaphorical link to the ship's logbook, the record of its voyage, implying the vessel's state was now critically recorded as being flooded. Over time, the term's use expanded beyond maritime contexts to describe any object or ground thoroughly saturated and rendered inert by an excess of water.

Structure: water (liquid) + log (to record, but here used in a nautical sense) - water: From Old English wæter, of Proto-Germanic origin; related to Dutch water and German Wasser. The core semantic element denoting the liquid H₂O. - log: From the practice of recording a ship's speed using a wooden log tied to a line. The noun came to be associated with the ship's record book and, by extension, the ship's progress or condition itself. In 'waterlog', it functions metaphorically to imply a ship's state or condition caused by water.