groundless
adj. 无理由的，无根据的
例句
I can say with confidence that such rumours were totally groundless.
我可以很有把握地说这些传言完全没有根据。
《柯林斯英汉双解大词典》
Fears that the world was about to run out of fuel proved groundless.
担心地球燃料即将用尽被证明是没有根据的。
Provided this technology is effective, those fears are groundless.
如果这项技术是有效的，那些担心则是没有根据的。
