凭空

凭空 [píng kōng]

1. ■ without ground [basis]; out of the void; out of thin air; without foundation; groundless; baseless:

凭空出现 emerge out of the void;

凭空杜撰 create groundless rumours;

他这种看法决不是凭空产生的。 His view is by no means without foundation.

你为什么凭空怀疑这消息的真实性? Why do you suspect the truth of the information?