Entry 3 senses · 3 variants Webster, 1913 Downhill /doun'-hĭl'/ · Down·hill · IPA /ˈdaʊnˌhɪl/ adv. a. n. 01 adv. Towards the bottom of a hill; as, water runs downhill. 1. Towards the bottom of a hill; as, water runs downhill. 02 a. Declivous; descending; sloping. 1. Declivous; descending; sloping. 03 n. Declivity; descent; slope. 1. Declivity; descent; slope. “On th' icy downhills of this slippery life.” — Du Bartas (Trans. ).