'mouthwatering' originates from English, specifically the compound words 'mouth' + 'water', where 'mouth' meant 'mouth' and 'water' meant 'water' (literally causing water in the mouth).

'mouthwatering' developed from the literal compound 'mouth-water' (an expression describing saliva in the mouth) and later formed the participial adjective 'mouth-watering' which became the modern single-word adjective 'mouthwatering'.

Initially, it meant 'causing the mouth to water' in a literal sense (i.e., producing saliva); over time it evolved into the common figurative meaning 'extremely appetizing' or 'highly attractive to the appetite'.