Not based on facts, and therefore wrong or not to be trusted. You use it for things people say or believe: unfounded rumours, unfounded claims, unfounded fears, unfounded accusations. The picture inside the word is a building with nothing underneath it — no foundation — so the whole thing is standing on air.

Not based on facts沒有事實根據, and therefore wrong or not to be trusted所以是錯的、不能相信的。You use it for你會用它形容 things people say or believe大家說的或相信的事情: unfounded rumoursunfounded rumours（無根據的傳言）, unfounded claimsunfounded claims（無根據的說法）, unfounded fearsunfounded fears（無根據的恐懼）, unfounded accusationsunfounded accusations（無根據的指控）。The picture inside the word is這個字裡的畫面是 a building with nothing underneath it一棟底下什麼都沒有的建築物——no foundation沒有地基——so the whole thing is standing on air所以整棟建築就是懸空立著的。

It is the word of choice when you want to push back on something calmly and seriously. A company says the reports about it are 'completely unfounded'; a court finds the complaint unfounded. That formal, official flavour is real: you will meet it constantly in news, statements, and legal writing, and much less in casual talk, where people say 'that's not true' or 'there's no proof'.

It is the word of choice這是首選的字 when you want to push back on something calmly and seriously當你想要冷靜而嚴肅地反駁某件事的時候。A company says一間公司可能會說 the reports about it are 'completely unfounded'關於它的報導「完全沒有根據」; a court finds法院則可能判定 the complaint unfounded這件申訴不成立。That formal, official flavour is real這種正式、官方的味道是真的: you will meet it constantly你會經常看到它 in news, statements, and legal writing在新聞、聲明和法律文件裡, and much less in casual talk但在日常對話裡少很多, where people say日常對話裡大家會說 'that's not true' or 'there's no proof'「that's not true」或「there's no proof」。

One thing worth noticing: 'unfounded' does not always mean the speaker was lying. A fear can be unfounded and completely sincere — you were genuinely afraid, there just turned out to be no reason. So the word attacks the evidence, not always the honesty.

One thing worth noticing有件事值得注意: 'unfounded' does not always mean the speaker was lyingunfounded 不代表說話的人在說謊。A fear can be unfounded一種恐懼可以是 unfounded 的 and completely sincere同時也完全是真心的——you were genuinely afraid你真的很害怕, there just turned out to be no reason只是後來發現沒有理由。So the word attacks所以這個字攻擊的是 the evidence證據, not always the honesty不一定是誠實。

The common partner phrases are worth learning whole: 'completely unfounded', 'entirely unfounded', 'unfounded rumours', 'prove unfounded' (meaning it turned out to have no basis after all).

The common partner phrases are worth learning whole常見的搭配詞值得整組學起來: 'completely unfounded''completely unfounded', 'entirely unfounded''entirely unfounded', 'unfounded rumours''unfounded rumours', 'prove unfounded''prove unfounded' (meaning it turned out to have no basis after all)（意思是最後證實根本沒有根據）。