Not admitting of passage or capable of being affected:
— A material impervious to water.
— Someone impervious to argument.

synonym: imperviable.

Roget 606: obstinate, tenacious, stubborn, obdurate, casehardened; inflexible etc. (hard) 323; balky; immovable, unshakable, not to be moved; inert etc. 172; unchangeable etc. 150; inexorable etc. (determined) 604; mulish, obstinate as a mule, pig-headed.    dogged; sullen, sulky; unmoved, uninfluenced unaffected.    willful, self-willed, perverse; resty^†, restive, restiff^†; pervicacious^†, wayward, refractory, unruly; heady, headstrong; entete [Fr.]; contumacious; crossgrained^†.    arbitrary, dogmatic, positive, bigoted; prejudiced etc. 481; creed-bound; prepossessed, infatuated; stiff-backed, stiff necked, stiff hearted; hard-mouthed, hidebound; unyielding; impervious, impracticable, inpersuasible^†; unpersuadable; intractable, untractable^†; incorrigible, deaf to advice, impervious to reason; crotchety etc. 608.    ... show more

Roget 471: impossible; not possible etc. 470; absurd, contrary to reason; unlikely; unreasonable etc. 477; incredible etc. 485; beyond the bounds of reason, beyond the bounds of possibility, beyond the realm of possibility; from which reason recoils; visionary; inconceivable etc. (improbable) 473; prodigious etc. (wonderful) 870; unimaginable, inimaginable^†; unthinkable.    impracticable unachievable; unfeasible, infeasible; insuperable; unsurmountable^†, insurmountable; unattainable, unobtainable; out of reach, out of the question; not to be had, not to be thought of; beyond control; desperate etc. (hopeless) 859; incompatible etc. 24; inaccessible, uncomeatable^†, impassable, impervious, innavigable^†, inextricable; self-contradictory.    out of one's power, beyond one's power, beyond one's depth, beyond one's reach, beyond one's grasp; too much for; ultra crepidam [Lat.].    ... show more

Roget 261: closed etc. v.; shut, operculated^†; unopened.    unpierced^†, imporous^†, caecal [Med.]; closable; imperforate, impervious, impermeable; impenetrable; impassable, unpassable^†; invious^†; pathless, wayless^†; untrodden, untrod.    unventilated; air tight, water tight; hermetically sealed; tight, snug.    ... show more

Roget 823: insensible, unconscious; impassive, impassible; blind to, deaf to, dead to; unsusceptible, insusceptible; unimpressionable^†, unimpressible^†; passionless, spiritless, heartless, soulless; unfeeling, unmoral.    apathetic; leuco-^†, phlegmatic; dull, frigid; cold blooded, cold hearted; cold as charity; flat, maudlin, obtuse, inert, supine, sluggish, torpid, torpedinous^†, torporific^†; sleepy etc. (inactive) 683; languid, half-hearted, tame; numbed; comatose; anaesthetic etc. 376; stupefied, chloroformed, drugged, stoned; palsy-stricken.    indifferent, lukewarm; careless, mindless, regardless; inattentive etc. 458; neglectful etc. 460; disregarding.    unconcerned, nonchalant, pococurante^†, insouciant, sans souci [Fr.]; unambitious etc. 866.    unaffected, unruffled, unimpressed, uninspired, unexcited, unmoved, unstirred, untouched, unshocked^†, unstruck^†; unblushing etc. (shameless) 885; unanimated; vegetative.    callous, thick-skinned, hard-nosed, pachydermatous, impervious; hardened; inured, casehardened; steeled against, proof against; imperturbable etc. (inexcitable) 826^†; unfelt.    ... show more

Polish: odporny, niewrażliwy