Synonyms and related words :
aidless, baseless, defenseless, empty, exceptionable, fatherless, faulty, flawed, friendless, groundless, guideless, helpless, idle, ill-founded, illogical, implausible, impossible, inadmissible, indefensible, inexpiable, insupportable, intolerable, leaderless, motherless, objectionable, pregnable, specious, unacceptable, unbased, undesirable, unforgivable, unfounded, unfriended, ungrounded, unjustifiable, unjustified, unpardonable, unprotected, unreasonable, unsound, unsuitable, unsupportable, unsupported, unsustainable, unsustained, unwarranted, vain, vulnerable, weak, without basis, without foundation