Synonyms for Impenetrable

Synonyms starting with letter I

• inscrutable

  incomprehensible, unaccountable, unfathomable
• incomprehensible

  unexplainable, knowledge, unaccountable
• impervious

  impassable, dense, impassible
• impermeable

  impervious, state, dense
• inexplicable

  incomprehensible, unfathomable, unaccountable
• impassable

  dense
• impregnable

  impassible, property, invulnerable
• inviolable

  impervious, invulnerable, dense
• inaccessible

  impregnable, impassable, impervious
• invulnerable
• indecipherable
• indestructible

  impervious
• inflexible
• invincible
• inconceivable
• indiscernible

  incomprehensible
• intricate
• involved
• insoluble
• immune
• incognizable

  incomprehensible
• impassible
• imperviable
• indomitable
• impracticable

  impassible
• insusceptible
• impossible to understand

  incomprehensible
• incoherent
• impassive
• invisible
• insurmountable
• inextricable
• incompressible
• inexpugnable
• inapproachable
• inscrutably
• indigestible
• iron
• indurate
• indurated