Synonyms of the word 
SHELLPROOF → BOMBPROOF - INVULNERABLE
shellproof
- adj. Resistant to shelling.
bombproof
- n. An air-raid shelter, a structure designed to give protection against air raids and bombs.
- adj. Sufficiently strong to resist the effects of a blast from a bomb.
invulnerable
- adj. Incapable of being injured; not vulnerable.
- adj. Unanswerable; irrefutable.
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