Possible Clues:

• Word that means the same thing if you put 'no' in front of it
• "You don't say!"
• 'Even *I* knew that!'
• 'It couldn't be more obvious!'
• 'Oh, that was so obvious!'
• ''That was silly of me!''
• ''Well, obviously!''
• Doltish interjection
• 'Bravo, Captain Obvious!'
• 'Yeah, no kidding!'