Similar word to unworkable:

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, unrealizable, unreasonable, unrecoverable, unthinkable, useless, visionary, way out