gradient, incline, side, pitch, steepness, hill, upslope, downslope, hillside, downhill, more...

plateau, flat, level, plain, valley

positive, negative, zero, steep, flat, inclined, declined, level, more...

steep, gentle, western, eastern, slippery, continental, southern, long, negative, northern, positive

downhill ski run,   slanting surface,   highland hillside,   side of a mountain,   uneven ground,   inclined surface,   an incline,   uneven floor,   side of a hill,   slanted area