As nouns the difference between pinnacle and steep
is that
pinnacle is the highest point while
steep is a liquid used in a steeping process.
As verbs the difference between pinnacle and steep
is that
pinnacle is to put something on a pinnacle while
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.
As an adjective steep is
of a near-vertical gradient; of a slope, surface, curve, etc that proceeds upward at an angle near vertical.