ejector

1. One that ejects, especially a device in a gun that ejects the empty shell after each firing.
2. A device using a jet of water, air, or steam to withdraw a fluid or gas from a space.

By common usage, a device used to remove debris and fluids by negative pressure. The correct term for such a device, however, is aspirator. See also aspirator.

1.A type of pump for ejecting liquid, as from a sump; induces fluid flow by entraining the liquid in the flow of a stream of air, steam, or water.
2. A cleanout, 1.

The noun has 2 meanings:

Meaning #1: a person who ousts or supplants someone else
  Synonym: ouster

Meaning #2: a mechanism in a firearm that ejects the empty shell case after firing
  Synonym: cartridge ejector