The word "chum" refers to a close friend or companion, but there are several other words with similar meanings. One of the most common synonyms for "chum" is "pal," which is short for "paladin," meaning a knightly hero. Another synonym for "chum" is "buddy," which is a term of endearment used between close friends. "Mate" is another synonym for "chum," originating from the nautical term for a fellow sailor. Other synonyms for "chum" include "comrade," "confidante," "ally," and "accomplice." Ultimately, these synonyms all describe someone who is a trusted and close companion.