Use the same trick with memorizing the meaning of stunned. Learn the verb. 1 stun somebody/something to make a person or an animal unconscious for a short time, especially by hitting them on the head (knock out): 'The animals are stunned before slaughter.' 2 stun somebody to surprise or shock somebody so much that they cannot think clearly or speak (surprise): 'Her words stunned me—I had no idea she felt that way.' 3 ​stun somebody to impress somebody very much (amaze): 'They were stunned by the view from the summit.' Do you think Malfoy was surprised or amazed?