1. impossible or extremely difficult to cross or pass over

Examples

• The raging river was uncrossable during the flood.
• Heavy snow made the mountain pass uncrossable for weeks.
• The deep canyon created an uncrossable barrier between the two villages.
• Without a bridge, the gorge remained uncrossable.
• The thick ice made the lake uncrossable on foot.
• War had turned the border into an uncrossable divide.