1. Not defended or capable of being defended
   - assailable, undefended, open

See also: vulnerable

• shell out
• shell parakeet
• shell plating
• shell shock
• shell stitch
• shell suit
• shell-less
• shell-shocked
• shellac
• shellac varnish
• shellac wax
• shellack
• shellbark
• shellbark hickory
• shelled
• sheller
• Shelley
• shellfire
• shellfish
• shellflower
• shelling
• shellproof
• shelly
• Shelta
• shelter