The word 'waterfowler' is a modern English compound agent noun, built from three native Old English elements. The core 'fowl' derives from the Old English 'fugol', meaning bird, which is a common Germanic term. It is prefixed by 'water' to specify the aquatic habitat of the targeted birds, distinguishing this hunter from one who hunts other game birds. The suffix '-er' is then added to denote the person engaged in this specific activity, following a very productive and transparent English word-formation pattern, resulting in a term that literally means 'a person associated with water birds'.

Structure: water + fowl + er water: Old English origin, meaning 'water', functioning as a modifier specifying the environment. fowl: Old English origin, meaning 'bird', functioning as the core noun element. er: Old English origin, an agent noun suffix, meaning 'a person who does or works with something'.