Formidable defense is a term associated with the ability of a team or country to protect their territory or goal. However, it can be synonyms with other powerful words such as impenetrable, invincible, impregnable, unbeatable, robust, resolute, unassailable, indomitable, and impervious. For example, when a country's military is impenetrable, it means that it is impossible to attack or invade, while a team with an unbeatable defense cannot be surpassed or beaten in the game. Therefore, the use of synonyms for formidable defense can help to create vivid and expressive descriptions, adding depth and meaning to any text or conversation where it is being used.