Hop up is a phrasal verb that means to increase or enhance the power, speed, or performance of something, typically a vehicle or machine. There are several synonyms for hop up, including beef up, boost, upgrade, improve, pimp out, soup up, hot rod, and modify. These phrases are commonly used in car culture and racing. Modifying a car's engine and components to increase its performance is a popular hobby for car enthusiasts. Hop up can also refer to increasing one's energy or enthusiasm, for example, by drinking caffeine or taking a supplement. Overall, hop up is a versatile phrase that can be applied to a wide range of situations where a boost in power or performance is desirable.