ill-founded complaint无理投诉
ill-founded plea理由不足的答辩
ill-founded unwarrantable无正当理由的
ADJ（形容词） Something that is ill-founded is not based on any proper proof or evidence. 毫无根据的; 无适当证据的
Suspicion and jealousy, however ill-founded, can poison a marriage.
怀疑和嫉妒，无论多么缺乏根据，也会毒害一桩婚姻。