'young-looking' originates from Modern English, combining the Old English word 'geong' (young) and the present participle 'looking' (from the verb 'look', Old English 'lōcian'), where 'geong' meant 'young' and 'lōcian' meant 'to look or have an appearance'.

'young' changed from Old English 'geong' into Middle English forms such as 'yong'/'young'; 'look' developed from Old English 'lōcian' through Middle English 'loken'/'looken' to Modern English 'look'. The compound adjective 'young-looking' was formed in Modern English by combining 'young' + the present participle 'looking'.

Initially the components referred simply to 'youth' ('young') and 'the act/appearance of looking' ('look'), but together as 'young-looking' the phrase came to mean specifically 'appearing younger than one's actual age' or 'having a youthful appearance'.