ignoramus comes from Latin ignoramus ('we do not know'), first person plural of ignorare ('not to know'). It was a legal endorsement on rejected indictments and became a byword for ignorance after Ruggle's 1615 play Ignoramus. The path is chiefly one of transmission: the word passes through the named languages and forms, with each stage preserving part of the modern shape. In present English, the noun sense is "an utterly ignorant or stupid person", so the historical development ends in a clearly identifiable modern dictionary use. The same base also appears in related forms such as ignorant, ignorance, and ignore. Its semantic neighborhood includes dunce, fool, blockhead, and dolt, which helps locate the modern sense without adding a separate etymological claim. The named historical forms include Latin ignorare and Latin gnoscere.