DOWNHILL
declivitous, downhill, downward-sloping
(adjective) sloping down rather steeply
downhill
(adverb) toward the bottom of a hill; “running downhill, he gained a lot of speed”
downhill
(adverb) toward a lower or inferior state; “your performance has been going downhill for a long time now”
downhill
(noun) a ski race down a trail
downhill
(noun) the downward slope of a hill
Source: WordNet® 3.1
Etymology
Adverb
downhill (comparative more downhill, superlative most downhill)
Down a slope.
Antonyms
• uphill
Adjective
downhill (comparative further downhill, superlative furthest downhill)
Located down a slope or hill.
Going down a slope or a hill.
(by extension) Easy.
(by extension) Deteriorating, getting worse.
Usage notes
• "Easy" sense: comparative and superlative are usually made with more and most.
• "Deteriorating" sense: often used with the verb "go".
Antonyms
• uphill
Noun
downhill (countable and uncountable, plural downhills)
(uncountable) The fastest of the disciplines of alpine skiing.
(countable) A rapid descent of a hill in related sports, especially in alpine skiing.
Verb
downhill (third-person singular simple present downhills, present participle downhilling, simple past and past participle downhilled)
To take part in downhill skiing.
Source: Wiktionary
Down"hill`, adv.
Definition: Towards the bottom of a hill; as, water runs downhill.
Down"hill`, a.
Definition: Declivous; descending; sloping. "A downhill greensward."
Congrewe.
Down"hill`, n.
Definition: Declivity; descent; slope.
On th' icy downhills of this slippery life. Du Bartas (Trans. ).
Source: Webster’s Unabridged Dictionary 1913 Edition