1. Impossible to achieve
   - unachievable, unattainable, unrealizable, unrealisable [Brit]

See also: impossible

Encyclopedia: Undoable

• Bolshevist
• Bolshevistic
• bolshevize
• bolshie
• bolshy
• bolster
• bolster up
• bolt
• bolt cutter
• bolt down
• bolt of lightning
• bolt out
• bolt-hole
• bolter
• bolti
• Boltonia
• Boltzmann
• Boltzmann distribution law
• Boltzmann's constant
• bolus
• Bolzano
• Bomarea
• Bomarea edulis
• Bomarea salsilla
• bomb