The word "掏空" is formed by combining the character "掏", meaning to dig or scoop out, which uses the hand radical 扌 to denote manual action, with the character "空", meaning empty, which uses the cave radical 穴 to imply void. Together, they create a compound where "掏" indicates the act of removing contents and "空" describes the resulting state, thus literally meaning to hollow out or empty completely.