Downhill

Part of speech: noun (n.)

Declivity; descent; slope. On th' icy downhills of this slippery life. Du Bartas (Trans. ).

Part of speech: adjective (a.)

Declivous; descending; sloping. "A downhill greensward." Congrewe.

Part of speech: adverb (adv.)

Towards the bottom of a hill; as, water runs downhill.