The word "光宗耀祖" is formed by combining two parallel verb-object phrases: "光宗" (meaning to bring honor to ancestors) and "耀祖" (meaning to bring glory to ancestors), where "光" and "耀" are synonymous verbs expressing glorification, and "宗" and "祖" are synonymous nouns referring to ancestors, resulting in a compound that reinforces the concept through repetitive structure.