impregnable /im-pregˈnə-bl/

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

• placer-gold
• placer-golds
• placers
• places
• place setting
• place settings
• placet
• placets
• place value
• place values
• placid
• placider
• placidest
• placidities
• placidity
• placidly
• placidness
• placidnesses
• placing
• placings
• placit
• placita
• placitory
• placitum
• plack