Related Clues:

• "Everybody knows that!"
• ''I shoulda known that''
• ''I should have known that!''
• "Okay, I get it already"
• Slangy 'That's obvious!'
• "How stupid of me!"
• Brow-slapper's syllable
• Word with a head slap
• 'Who doesn't know that?!'
• “Obviously!”
• ''I knew that!''
• 'Obviously'
• 'Well, of course!'
• 'No shit, Sherlock'
• Response to the obvious