The ignorant accepts their ignorance and tries to discover the truth. Research, holistically evaluate, listen to others, and discern to discover more about the unknown and make it known. Example: The ignorant asks for directions to a destination he is unclear of.
The ignoramus insists on staying ignorant by virtue of a lack of introspection and/or intelligence/wisdom and maybe even a function of ego. They refuse to learn, unlearn, or relearn. Unfortunately, the characteristic of the ignoramus is such that he will insist on being ignorant on several matters and is not an isolated case, ergo, the ignoramus is much more inclined to be ignorant of many things in the universe. Example: The ignoramus would rather be lost than ask for direction.
Unfortunately, the latter is a prevalent event, even among my readers. An example is a comment from my post on dysmenorrhea.