1. Incapable of being ascended
   - unscalable 
2. Incapable of being surmounted or climbed
   - unsurmountable

See also: impassable, unpassable

• PO box number
• Po Hai
• Po River
• po-faced
• Poa
• Poa nemoralis
• Poa pratensis
• Poaceae
• poach
• poached
• poached egg
• poacher
• poaching
• POB
• Pobeda Peak
• Pobedy Peak
• Pocahontas
• Pocatello
• pochard
• pock
• pocked
• pocket
• pocket battleship
• pocket billiards
• pocket borough