cool as a cucumber

1. Calm and composed, self-possessed, as in Despite the mishap Margaret was cool as a cucumber. This idiom may be based on the fact that in hot weather the inside of cucumbers remains cooler than the air. [c. 1600] For a synonym, see cool, calm, and collected.

Related Words

• comfortable 
• composed 
• cool 
• easygoing 
• laid-back 
• peaceful 
• placid 
• poised 
• quiet 
• sedate 
• smooth 
• tranquil 
• unflappable