impenetrable /im-penˈi-trə-bl/

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

impenetrabilˈity noun

impenˈetrably adverb

• grey-wethers
• grey whale
• grey whales
• grey wolf
• grey wolves
• GRI
• gribble
• gribbles
• grice
• gricer
• gricers
• grices
• gricing
• gricings
• grid
• Grid
• gridder
• gridders
• griddle
• griddle-cake
• griddle-cakes
• griddle car
• griddle cars
• griddled
• griddles