Related Clues:

• Dated expression of appreciation
• Inspiring fear
• Something wonderful, in old slang
• Car part, slangily
• Badass
• Physicist's measure
• "Really cool!"
• Unit at a reactor
• "Totally cool!"
• "Far out!"
• ''Sweet!''
• Portentous
• Really cool
• X-ray spec?
• 'Lovely!,' in dated slang