'keen-scented' originates from English, combining the adjective 'keen' and the adjective-forming past participle 'scented' (from 'scent'), where 'keen' meant 'sharp' (intense) and 'scent' meant 'smell'.

'keen' developed through Middle English 'kene' (from Old English 'cēne' in senses related to boldness/keenness), while 'scent' came into English via Old French 'sentir' (from Latin 'sentire' meaning 'to feel, to perceive'); the compound 'keen-scented' is a modern English formation combining these elements to describe sharpness of smell.

Initially 'keen' had senses including 'brave' or 'bold' in older English, but its sense shifted toward 'sharp' or 'intense'; combined with 'scented' the modern meaning is 'having a sharp sense of smell'.