The phrase "heave overboard" means to discard or throw away something, typically from a ship or boat into water. Some synonyms for this term include "jettison," "discard," "cast off," "dump," "toss," "reject," "abandon," and "dispose of." Each of these words conveys the idea of getting rid of something that is unwanted or no longer needed. While "heave overboard" is a more specific nautical term, these synonyms offer a range of ways to express the same idea in everyday language. Whether one is talking about tossing out old clothes or unloading excess baggage, there are plenty of alternatives to choose from.