1. That may be navigated.

2. Navigableness.

Nuttall's Standard dictionary of the English language By Nuttall, P.Austin

• navicable,
• navigatable,
• navagable,
• navigagte,
• naviagable,
• salvigable,
• savagable,
• bavigable,
• mavigable,
• javigable,
• havigable,
• navigble,
• naivgable,
• naviagble,
• navigabel,
• navigible,
• inavigable,
• manirable,
• inavigably,
• navigablenes

• navigability.

The adjective form of the word "navigable" is "navigable".

The plural form of the word "navigable" is "navigables".

The singular form of the word "navigable" is "navigability"