The word 动作 is formed by combining two characters that each convey related ideas of movement and activity. The first character, 动 (dòng), fundamentally means "to move" or "to act". The second character, 作 (zuò), carries the core meaning of "to do", "to make", or "to work". When placed together, they create a compound where the meanings merge and reinforce each other, resulting in the unified concept of "action" or "movement", representing physical motion or a specific deed.