The word 朴素 is formed by combining the character 朴, which originally denotes unprocessed wood and is composed of the wood radical (木) indicating material and the phonetic component 卜 suggesting pronunciation, with the character 素, which derives from a representation of plain woven cloth and conveys the idea of something basic, white, or unadorned. Together, they create a compound where both characters semantically contribute to the meaning of simplicity, plainness, or modesty.