3
firm
3
hermetically sealed(expression, adjective, idiom)
3
occult(adjective, obscure, dark, deep, mysterious)
3
pressure-tight(adjective, tight, proof, impervious)
3
proof(adjective, tight, impervious)
3
secluded(adjective, close, quiet, obscure, dark)
2
abstruse(obscure, dark, deep, mysterious, secret)
2
arcane(obscure, solid, complex, deep, mysterious)
2
gastight(adjective, tight, proof, impervious)
2
heavy(adjective, obscure, complex, deep, thoughtful)
2
cabalistic(obscure, solid, complex, deep, mysterious)
2
choked(adjective, closed)
2
cloistered(close, quiet, private, isolated, secluded)
2
close(quiet, obscure, solid, dark, dense)
2
compact
2
concealed(obscure, complex, deep, mysterious, secret)
2
cryptic(obscure, dark, complex, unknown, hidden)
2
enigmatic
2
fast
2
gasproof
11 years ago|4.8k views|share |citing 
APASmart Define. (2015). hermetic thesaurus. Retrieved September 25, 2026, from https://smartdefine.org/hermetic/thesaurus/synonyms
ChicagoSmart Define. 2015. "hermetic thesaurus" https://smartdefine.org/hermetic/thesaurus/synonyms (accessed September 25, 2026).
HarvardSmart Define 2015, hermetic thesaurus, Smart Define, viewed 25 September, 2026, <https://smartdefine.org/hermetic/thesaurus/synonyms>.
MLASmart Define. "hermetic thesaurus" 10 April 2015. Web. 25 September 2026. <https://smartdefine.org/hermetic/thesaurus/synonyms>