impenetrable /im-penˈi-trə-bl/

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

impenetrabilˈity noun

• noctuary
• Noctuas
• noctuid
• Noctuidae
• noctuids
• noctule
• noctules
• nocturn
• nocturnal
• nocturnally
• nocturnals
• nocturne
• nocturnes
• nocturns
• nocuous
• nocuously
• nocuousness
• nocuousnesses
• nod
• nodal
• nodalise
• nodalised
• nodalises
• nodalising
• nodalities