unobtainable (adjective) impossible: beyond the bounds of possibility
Sinonime: absurd,
beyond, contrary to reason, cureless,
futile, hardly possible,
hopeless, hundred-to-one, impassable,
impervious, impracticable,
impractical, inaccessible,
inconceivable, inexecutable, infeasible,
insurmountable, irrealizable, irreparable, no-go, no-way, no-win, not a prayer, out of the question,
preposterous,
too much, unachievable,
unattainable, uncorrectable, unfeasible,
unimaginable, unobtainable,
unreasonable, unrecoverable, unthinkable, unworkable,
useless,
visionary, way out
Antonime: achievable,
believable, obtainable,
possible,
reasonable, tenable