Explanation:

- The word "noted" typically describes someone or something that is well-known or famous for a specific reason.

- Option 1: "Famous" - Similar to "noted," this means being well-known or widely recognized. Not an antonym.

- Option 2: "Obscure" - This means not well-known or difficult to understand, making it the opposite of "noted."

- Option 3: "Frank" - Relates to being open, honest, and direct, and doesn't relate to "noted" in terms of notoriety or recognition.

- Option 4: "Celebrated" - Similar to "noted" and "famous," meaning highly regarded or acknowledged by many.