unfounded

About 1.20 uses per million words.

Meaning

1. adjective Having no strong foundation; not based on solid reasons or facts.

   an unfounded report; unfounded fears

2. adjective Not having been founded or instituted.
3. adjective Bottomless.

Similar words

groundless baseless unwarranted unsupported idle unsubstantiated ungrounded ill-founded unjustified unconfirmed

Often followed by

and in as charges or accusations fears claims rumors