impregnable /im-pregˈnə-bl/

1. That cannot be captured, broken into or taken by force
2. Which cannot be overcome, unassailable

• quilted
• quilter
• quilters
• quilting
• quilting bee
• quilting bees
• quilting-cotton
• quilting-frame
• quilting-frames
• quilting party
• persing
• Persism
• persist
• Persist
• persisted
• persistence
• persistences
• persistencies
• persistency
• persistent
• persistent cruelty
• persistently
• persistents
• persistent vegetative state
• persisting