Whizzer is a slang term that refers to a person known for their speed or ability to move quickly. Some synonyms for this word include speedster, rocket, bullet, bolt, blazer, jet, and swift. These words are commonly used to describe individuals who excel in sports like track and field, cycling, and racing. Additionally, they can also describe individuals who have fast reflexes or are quick to respond to situations. Overall, using synonyms for the term whizzer can add variety to your language and help you effectively communicate the speed and agility of a person or object.