impenetrate /im-penˈi-trāt/

1. To permeate
2. To penetrate thoroughly

impenetrāˈtion noun

• unsoundest
• unsoundly
• unsoundness
• unsoundnesses
• unsourced
• unsoured
• unsown
• unspar
• unspared
• unsparing
• unsparingly
• unsparingness
• unsparingnesses
• unsparred
• unsparring
• unspars
• unspeak
• unspeakable
• unspeakableness
• unspeakablenesses
• unspeakably
• unspeaking
• unspeaks
• unspecialised
• unspecialized