sink

fall heavily or suddenly; decline markedly

descend into or as if into some soft substance or place

cause to sink

plumbing fixture consisting of a water basin fixed to a wall or floor and having a drainpipe

a process that acts to absorb or remove energy or a substance from a system

“the ocean is a sink for carbon dioxide”

appear to move downward

a depression in the ground communicating with a subterranean passage (especially in limestone) and formed by solution or by collapse of a cavern roof

fall or descend to a lower place or level

a covered cistern; waste water and sewage flow into it

go under

pass into a specified state or condition