impenetrable /im-penˈi-trə-bl/

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

• equation of time
• equations
• equative
• Equatoguinean
• equator
• equatorial
• equatorially
• equatorials
• equatorial telescope
• equatorial telescopes
• equators
• equerries
• equerry
• equestrian
• equestrianism
• equestrianisms
• equestrians
• equestrienne
• equestriennes
• equi-
• equiangular
• equiangularities
• equiangularity
• equiangular spiral
• equibalance