The word 敲门 is formed by directly combining two meaningful characters: 敲 (qiāo), which depicts the action of striking or tapping, and 门 (mén), which represents a door. Together, they create a clear, concrete image of the physical act, a hand knocking upon a door, to express the concept of "to knock on a door". This formation follows a natural, action-object logic where the verb logically operates upon the noun, resulting in an intuitive and visually descriptive compound.