baseless
base·less / ˈbeslɪs ; ˈbeɪsləs /adjective
1. not based on facts or good reasons – used to show disapproval无根据的; 无缘无故的〔含贬义〕;SYNunfounded
baseless rumours / charges / accusations毫无根据的谣传/没有根据的指控/无端的指责