There are various synonyms for the phrase "case of nerve" or "nerve." Some of the most common synonyms are audacity, boldness, confidence, courage, daring, fearlessness, grit, pluck, and spine. Having a "case of nerve" can refer to exhibiting brave or daring behavior, often in a situation that requires a lot of courage or confidence. Additionally, a person with a "case of nerve" may be described as audacious or bold in their actions. These synonyms can be interchanged depending on the context of the situation and the level of confidence or courage required to navigate it.