"Pluck up" is a phrasal verb that means to summon courage or confidence. It can be replaced with synonyms like "gather courage," "take heart," "be brave," "put on a brave face," "take a deep breath," "face the music," and "steel oneself." These synonyms can be used interchangeably, depending on the context and the level of courage required. For instance, "take a deep breath" is used when one needs to calm down before summoning courage, while "be brave" is used when a daunting task needs to be undertaken. Regardless of the synonym used, "pluck up" is an essential trait that enables individuals to face life's challenges with confidence and poise.