impervious

impervious adjective  airtight, blind to, blocked, buffered, callous, closed, deaf to, dense, hard, hard to convince, hardened, hermetic, impassive, impeditus, impenetrabilis, imperforate, impermeable, impersuadable, impersuasible, imperturbable, imperviable, impervious, inaccessible, incapable of being affected, incapable of being impaired, incapable of being influenced, incaaable of being injured, indifferent, indurate, indurated, insensitive, inured, invious, locked, not permitting passage, not permitting penetration, obstinate, obstructed, obtuse, opaque, pachydermatous, pathless, protected, safe, sealed, seared, shielded, shut, steeled, stubborn, thick, thick-skinned, tight, unaffected, unamenable, uninfluenced, unmovable, unmoved, unopened, unpassable, unperforated, unpierceable, unreachable, unreceptive, unresponsive, unswayable, unyielding, waterproof, watertight

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See also: inexpressive, insuperable, insusceptible, obdurate, opaque, safe, torpid, unaffected