'ruddy' originates from Middle English, specifically from forms such as 'ruddi' or 'rudie', where the root meant 'red' (related to 'red').

'ruddy' developed from Middle English 'ruddi' which in turn derives from Old English/Proto-Germanic words for 'red' (compare Old English 'rēad' meaning 'red'), eventually becoming the modern English 'ruddy'.

Initially it meant 'red' or 'reddish'; over time it came to mean 'having a healthy red complexion' and later acquired a colloquial use as a mild intensifier (euphemistic for 'bloody').