"Brutum Fulmen" is a Latin phrase which literally means "a harmless thunderbolt". When used in modern language, it can be interpreted as a statement or action that is sound and fury but ultimately has little or no effect, or a warning that is unenforceable. Synonyms for this phrase include "empty threat", "paper tiger", "hot air", "bluster", "mockery", "hollow promise", "bark without bite", "smoke and mirrors", and "false alarm". These terms describe situations where someone or something appears intimidating or powerful, but is ultimately ineffective. It is important to recognize Brutum Fulmen to avoid being lulled into a false sense of security.