Meaning: A place of torment for spiritual beings.
Usage: A place of no return. A cause or investment that will never yield returns.
Example: Putting money into that old house is a bottomless pit.
Rev 20:3 And cast him into the bottomless pit, and shut him up, and set a seal upon him, that he should deceive the nations no more, till the thousand years should be fulfilled: and after that he must be loosed a little season.