To make someone unable to think or feel properly. The loud noise was enough to stupefy anyone in the vicinity.
To astonish or shock someone to the point of being unable to react. The magician's final trick was so impressive it managed to stupefy the entire audience.
To dull or deaden the senses or faculties of, often through drugs, alcohol, or shock. The sedative was strong enough to stupefy the patient within minutes.