Having no basis or foundation in fact
Her self-esteem was slowly sinking into a bottomless pit.
I have visited two such Bottomless Ponds in one walk in this neighborhood.
After the overthrow of the Beast and the kings of the earth, Satan is imprisoned in the bottomless pit a thousand years (xx.
He actually made the plunge into that bottomless black pool sound almost enticing.
The sea floor is here rent by a chasm, known as the "Bottomless Pit," the waters having a depth of 65 ft.