Related Clues:

• Level-headed
• 'Sweet!'
• Hard to fluster
• Calm and relaxed
• Beatnik's 'all right'
• Beatnik's expletive
• 56, say
• Not nervous
• Like the proverbial cucumber
• Socially adept, in slang
• 'Groovy'
• Like laid-back jazz
• Not exactly friendly
• "Sounds good"
• Close to cold