As adjectives the difference between steep and vertical
is that
steep is of a near-vertical gradient; of a slope, surface, curve, etc that proceeds upward at an angle near vertical while
vertical is along the direction of a plumbline or along a straight line that includes the center of the earth.
As nouns the difference between steep and vertical
is that
steep is a liquid used in a steeping process while
vertical is a vertex or zenith.
As a verb steep
is (ambitransitive) to soak an item (or to be soaked) in liquid in order to gradually add or remove components to or from the item.