mouth-watering

the compound adjective 'mouth-watering' is a vivid example of english's capacity for descriptive, figurative formation. it is built from two ancient germanic roots: 'mouth', from old english 'mūþ', and 'water', from old english 'wæter'. the concept literally describes the physiological reaction of salivation in anticipation of food. the '-ing' suffix, also of old english origin, transforms the verbal action into a permanent descriptive quality. the term's logic is transparently sensory, directly linking the physical effect (watering of the mouth) to the cause (extremely appealing food), and has been used figuratively since the 19th century to describe anything intensely desirable.

Structure: mouth (body part) + water (liquid) + ing (adjective suffix) mouth: old english, refers to the oral cavity, the organ of eating and tasting. water: old english, refers to the clear liquid, here used to signify saliva. ing: old english, suffix forming adjectives from verbs or nouns, indicating 'having the quality of'.