impenetrable Synonyms - page 3

hard gummous grumous gordian formidable cryptic confusing condensed cabalistic bushy bewildering baffling arcane appressed alchemistic alchemic caecal caked compressed complicated complex compacted compact closed cassideous caseous adamantine jellied insolvable insoluble inscrutably inscrutable inexpugnable inexplicable indiscoverable indestructible inspissated insuperable irresolvable invulnerable involved invious inviolable invincible investigable insusceptible indecipherable incompressible incomprehensible impermeability