Speedster is a term used to describe someone who is very fast, usually in the context of racing. The term can be broken down into two crossword solutions: RACER (5 letters) and Jehu (4 letters). RACER is a term used to describe someone who competes in a race, while Jehu is an Old Testament figure known for his swift chariot driving. Together, these two words form the term Speedster, which is used to describe someone who is very fast.