0
bad
0
believable(sound, reasonable, rational)
0
bond
0
bound(adjective, safe, sheltered, protected, locked)
0
brassbound
0
bulletproof
0
buttoned down(expression, adjective, safe, sheltered, protected)
0
callous
0
closely adhering(expression, idiom)
0
compressed
0
concrete
0
condensed
0
condonable(sound, reasonable, rational)
0
consistency
0
constitute
0
constrained(firm, true, fixed, constant, steadfast)
0
consume
0
continuance
0
credible(sound, reasonable, rational)
0
dense
11 years ago|6.3k views|share |citing 
APASmart Define. (2015). impregnable thesaurus. Retrieved September 21, 2026, from https://smartdefine.org/impregnable/thesaurus/synonyms
ChicagoSmart Define. 2015. "impregnable thesaurus" https://smartdefine.org/impregnable/thesaurus/synonyms (accessed September 21, 2026).
HarvardSmart Define 2015, impregnable thesaurus, Smart Define, viewed 21 September, 2026, <https://smartdefine.org/impregnable/thesaurus/synonyms>.
MLASmart Define. "impregnable thesaurus" 10 April 2015. Web. 21 September 2026. <https://smartdefine.org/impregnable/thesaurus/synonyms>