unfounded

adjective3

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

   • an unfounded report; unfounded fears
2. •
   Not having been founded or instituted.

   • Even the great world as yet undiscovered, the cities as yet unfounded, and the history as yet unwritten, are lost: fallen from the beginning. — 1980
3. •
   (no longer used) Bottomless.

   • […] from them I go This uncouth errand sole, and one for all My self expose, with lonely steps to tread Th’ unfounded deep […] — 1667