Synonyms for sink

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

• sinkhole

a covered cistern (noun)

• cesspool
• cesspit
• sump

fall or descend to a lower place or level (verb)

• drop

pass into a specified state or condition (verb)

• pass
• lapse

go under (verb)

• settle

descend into or as if into some soft substance or place (verb)

• subside

appear to move downward (verb)

• dip

fall heavily or suddenly (verb)

• slump

fall or sink heavily (verb)

embed deeply (verb)

• bury