The word "彻底" is formed by combining the character "彻", meaning to penetrate or thorough, which itself is composed of the radical "彳" (indicating movement) and the component "切" serving primarily as a phonetic element, with the character "底", meaning bottom or base, composed of the radical "广" (indicating shelter) and the component "氐" acting as a phonetic and semantic element. Together, they create a compound where the literal idea of penetrating to the bottom evolves into the abstract meaning of thoroughness or completeness.