Related Clues:

• Homer Simpson's contribution to the OED
• Slap-on-the-forehead cry
• 'I blew it,' to Homer
• First note in sol-fa scale
• Sound trademark of 20th Century Fox
• "I blew it," to Homer
• 'I'm an idiot!'
• Dolt's response
• Homer says it a lot
• "Like, no-brainer!"
• 'I am so stupid!'
• 'I would have thought it was obvious'
• Play-__: kids' clay
• "Dumb, dumb, dumb!" to Homer Simpson
• "I'm an idiot!"