Related Clues:

• Cool, in the '40s
• Viral inflammation, informally
• Cool, in the '50s
• Hardly old-fashioned, in an old-fashioned way
• Not at all nerdy
• Cadence shout
• Not at all square
• Fanny pack spot
• Place for a holster
• "In the old grooveroo"
• Holster location
• Like many a 21-Down
• Up on things, daddy-o
• Cool, as a daddy-o
• Cool, like a cat