impenetrate /im-penˈi-trāt/

1. To permeate
2. To penetrate thoroughly

impenetrāˈtion noun

• thunderflashes
• thunder god
• thunder gods
• thunderhead
• thunderheads
• thunderier
• thunderiest
• thundering
• Thundering Legion
• thunderingly
• thunderless
• thunderlike
• thunder-master
• thunderous
• thunderously
• thunderousness
• thunderousnesses
• thunder peal
• thunder peals
• thunder-plump
• thunder-plumps
• thunders
• thunder sheet
• thunder sheets
• thundershower