'rosiness' originates from the English word 'rosy', which is derived from the Latin word 'rosaceus', where 'rosa' meant 'rose'.

'rosaceus' transformed into the Old French word 'rosé', and eventually became the modern English word 'rosy', from which 'rosiness' is derived.

Initially, it meant 'having the color of a rose', but over time it evolved into its current meaning of 'having a healthy pink or red color'.