impenetrable /im-penˈi-trə-bl/

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

• progradation
• progradations
• prograde
• prograded
• progrades
• prograding
• program
• programmabilities
• programmability
• programmable
• programmable read-only memory
• programmables
• programmatic
• programmatically
• programme
• programmed
• programmed learning
• programme evaluation and review technique
• programme music
• programme picture
• programmer
• programmers
• programmes
• programme trader
• programme trading