Steep.

Slippery; steeply sloping. rare.

Extending to a great height; elevated, lofty.

High; steep. Obsolete.

That rises or projects directly upwards.

Precipitous.

Steep.

Of a cliff, precipice, etc.: steep or vertical; very high. Also in figurative contexts. Now rare.

Precipitous; perpendicular.

(a) n. a slope, the side of a hill; (b) adj. precipitous.

Overhanging; jutting or leaning over; sloping or slanting, or placed on a steep slope. Obsolete.

Of a roof, rafter, etc.: set at a sharp angle; steeply sloping; (also of a building) having such a roof.

Of a rock, rampart: Having a precipitous face or side. Obsolete except in steeped-to = steep-to, adj.

Nearly vertical; very steep, precipitous.

Steep; full of steep places; precipitous.

Having a (considerable) declivity or slope; steep.

Somewhat steep, rather precipitous.

cut out in the form of an escarp.

Of a surface: sloping sharply or steeply.