If you describe a rumour, belief, or feeling as ~, you mean that it is wrong and is not based on facts or evidence.
There were ~ rumours of alcohol abuse...
The allegations were totally ~...
= groundless
ADJ
If you describe a rumour, belief, or feeling as ~, you mean that it is wrong and is not based on facts or evidence.
There were ~ rumours of alcohol abuse...
The allegations were totally ~...
= groundless
ADJ
Collins COBUILD. Толковый словарь английского языка для изучающих язык Коллинз COBUILD (международная база данных языков Бирмингемского университета) . 2012