The word "不伦不类" is formed by directly repeating the negating character "不" (meaning "not") before each of the two substantive characters: "伦" (referring to proper human relations or ethical order) and "类" (referring to category or type). This sequential negation results in a literal composition of "not伦 not类", which inherently conveys the idea of something being neither conforming to proper norms nor fitting into a clear category.