This word is acceptable for play in the UK dictionary that is being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

adj. not navigable; impossible to sail through

adj. that cannot be used for any reason.

Not navigable; incapable of being navigated; that may not be sailed on.

adj. incapable of being navigated

"On either hand they confront the naked poles, and they recoil from unnavigable space to an intenser struggle among themselves."

unpassable    impassable   

dissolved    intelligence/human    softcar    europan    outweb