impenetrable /im-penˈi-trə-bl/

1. Incapable of being penetrated
2. Impervious
3. Inscrutable
4. Occupying space exclusively (physics)

impenetrabilˈity noun

• speciocides
• speciosities
• speciosity
• specious
• speciously
• speciousness
• speciousnesses
• speck
• specked
• speckier
• speckies
• speckiest
• specking
• speckle
• speckled
• speckledness
• specklednesses
• speckled trout
• speckled trouts
• speckle interferogram
• speckle interferograms
• seame
• seamed
• sea mell
• sea mells