Related Clues:

• Composed
• Unruffled
• Unlikely to crack
• Unflappable
• Perfectly composed
• Calm and composed
• Not at all red hot?
• Unlikely to be a flapper in Salad Days?
• Untroubled by heat or exertion
• Very calm and unexcited like hothouse plant surprisingly
• Keeping calm
• Possible crossword clue for "Refrigerate"?