60 entries under tight topic. ×

2
consolidated(adjective, close, solid, short, substantial)
2
crowded(adjective, close, solid, short, substantial)
2
jam-packed(adjective, close, solid, short, substantial)
2
packed(adjective, close, solid, short, substantial)
2
retentive(adjective, proof, impervious, hermetic)
2
water-tight(adjective, proof, impervious, hermetic)
1
air-locked(adjective, proof, impervious, hermetic)
1
air-proof(adjective, proof, impervious, hermetic)
1
airproof(adjective, proof, impervious, hermetic)
1
close-grained(adjective, close, set, hard, tough)
1
dampproof(adjective, proof, impervious, hermetic)
1
enclosed(adjective, proof, impervious, hermetic)
1
gas-tight(adjective, proof, impervious, hermetic)
1
gas proof(adjective, proof, impervious, hermetic)
1
gastight(adjective, proof, impervious, hermetic)
1
hermetical(adjective, proof, impervious, hermetic)
1
hermetically-impervious(adjective, proof, impervious, hermetic)
1
hermetically-sealed(adjective, proof, impervious, hermetic)
1
leaktight(adjective, proof, impervious, hermetic)
1
liquid-tight(adjective, proof, impervious, hermetic)
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APASmart Define. (2015). impermeable thesaurus. Retrieved September 26, 2026, from https://smartdefine.org/impermeable/thesaurus/synonyms
ChicagoSmart Define. 2015. "impermeable thesaurus" https://smartdefine.org/impermeable/thesaurus/synonyms (accessed September 26, 2026).
HarvardSmart Define 2015, impermeable thesaurus, Smart Define, viewed 26 September, 2026, <https://smartdefine.org/impermeable/thesaurus/synonyms>.
MLASmart Define. "impermeable thesaurus" 14 April 2015. Web. 26 September 2026. <https://smartdefine.org/impermeable/thesaurus/synonyms>