downhill

The word 'downhill' is a transparent compound formed from two native English elements. 'Down' originates from the Old English phrase 'of dūne', meaning "from the hill," which over time was shortened and generalized to signify any downward direction. 'Hill' comes from the Old English 'hyll', a common Germanic term for a natural elevation. When combined, the literal meaning "in the direction down a slope" was immediately clear. This concrete sense later facilitated metaphorical extensions, such as describing a decline in fortunes or, in modern sports, a specific type of racing conducted on a descending course.

Structure: down (direction) + hill (elevated land) - down: From Old English dūne, short for of dūne "from the hill". Its functional role is as an adverb/adjective indicating a downward direction or lower position. - hill: From Old English hyll, of Proto-Germanic origin. Its functional role is as a noun denoting a naturally raised area of land.