DECLIV'ITY, noun [Latin sloping.] Declination from a horizontal line; descent of land; inclination downward; a slope; a gradual descent of the earth, of a rock or other thing: chiefly used of the earth, and opposed to acclivity, or ascent; the same slope, considered as descending, being a declivity and considered as ascending, an acclivity.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI