There are several synonyms for the phrase "cast away" which means to discard or abandon something or someone. Some of these synonyms include "jettison," "abandon," "ditch," "forsake," "disown," "reject," "throw out," "discard," and "dump." Each of these words implies getting rid of something or someone, but they may carry different connotations. For example, "jettison" connotes a deliberate act of getting rid of excess baggage or unnecessary weight to keep a vessel from sinking, while "abandon" implies leaving someone or something without any intention of returning. Whatever the synonym used, it is clear that the action is taken to leave something behind.