Braintwister synonyms | phrases

Phrases with similar meaning for Braintwister

• closed book

  brain-teaser, mystery
• tough nut to crack

  brain-teaser, mystery
• brain-twister

  brain-teaser
• knotty question

  brain-teaser
• mind-boggler

  brain-teaser
• tough proposition
• brain-teaser
• magic number
• skeleton in cupboard
• privileged information
• confidential information