ill-founded

 Longman Dictionary of Contemporary English 5++朗文当代英语 5++LDOCE 5++朗文 5++ˌill-ˈfounded adjective formal  UNTRUEbased on something that is untrue 理由不充分的，没有根据的，站不住脚的 His fears proved ill-founded. 他的恐惧事实证明是杞人忧天。

Examples from the Corpus

ill-founded• But any doubts about Marillion's future were clearly ill-founded.• The experience of the 1970s, further, demonstrated that the principal argument in favour of flexible exchange rates was ill-founded.• Suppositions built on postcards and photographs might be as ill-founded as his short-lived suspicions of being followed the night before.• The trouble is that the revised version of the legend of the Courts of Love is as ill-founded as the old one.• The whole enterprise was ill-founded from the start.• But the case of Auerbach merely serves to illustrate how ill-founded the criterion is.• ill-founded worries

ˌill-ˈfounded adjectiveChineseSyllable  

on is Corpus based that something untrue

ill-founded
ˌill-ˈfounded adjective formal
based on something that is untrue:
    His fears proved ill-founded.

ill-foundedBrE /ˌɪl ˈfaʊndɪd/ 🔊NAmE /ˌɪl ˈfaʊndɪd/ 🔊 adjective (formal) not based on fact or truth 凭空的；无根据的；毫无理由的◆All our fears proved ill-founded. 我们所有的担心结果都证明是杞人忧天。🔊🔊 OPP well founded