bottomless pit
Definitions
A chasm or abyss of immeasurable depth.
A situation or condition that seems to have no end or limit, often implying a state of despair or an insatiable demand.
Examples
Trying to satisfy his endless demands for money felt like throwing coins into a bottomless pit.
The deep, dark canyon looked like a bottomless pit that stretched down into the center of the earth.
Synonyms
abyss chasm void infinite depth unfathomable gulf bottomless chasm