declivity

noun declivity

• declination — the angular distance, esp in degrees, of a star, planet, etc, from the celestial equator measured north (positive) or south (negative) along the great circle passing through the celestial poles and the body
• descent — A descent is a movement from a higher to a lower level or position.
• inclination — a disposition or bent, especially of the mind or will; a liking or preference: Much against his inclination, he was forced to resign.
• slope — to have or take an inclined or oblique direction or angle considered with reference to a vertical or horizontal plane; slant.