Wham/wæm/ Definition 1 of 3Pro Tip 1/3Sudden Surprise Use 'wham' to describe something surprising that happens very quickly. Everything was quiet, and then wham, fireworks started. Pro Tip 2/3Expressive Sound 'Wham' is often used to mimic the sound of a sudden impact or collision. The books fell off the shelf with a loud wham. Pro Tip 3/3Not Literal Sometimes 'wham' is used for dramatic effect, not to describe an actual sound. She was considering her options when wham, she had a great idea.