impenetrable /im-penˈi-trə-bl/

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

• icer
• ice rink
• ice rinks
• icers
• ice run
• ice runs
• ices
• ice sheet
• ice sheets
• ice shelf
• ice shelves
• ice show
• ice shows
• ice skate
• ice-skate
• ice-skated
• ice-skater
• ice-skaters
• ice skates
• ice-skates
• ice-skating
• ice spar
• ice spars
• icestone
• ice storm