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

• sinkhole
• swallow hole

2. (noun) a covered cistern; waste water and sewage flow into it

• cesspit
• cesspool
• sump

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

• drop
• drop down

4. (verb) pass into a specified state or condition

• lapse
• pass

5. (verb) go under,

• go down
• go under
• settle

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

• subside

7. (verb) appear to move downward

• dip

8. (verb) fall heavily or suddenly; decline markedly

• fall off
• slump

9. (verb) fall or sink heavily

• slide down
• slump

10. (verb) embed deeply

• bury

1. (noun) plumbing fixture consisting of a water basin fixed to a wall or floor and having a drainpipe

• plumbing fixture

2. (noun) (technology) a process that acts to absorb or remove energy or a substance from a system

• action
• activity
• natural action
• natural process

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

• depression
• natural depression

4. (noun) a covered cistern; waste water and sewage flow into it

• cistern

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

• change posture

6. (verb) cause to sink

• displace
• move

7. (verb) pass into a specified state or condition

• move

8. (verb) go under,

• come down
• descend
• fall
• go down

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

• come down
• descend
• fall
• go down

10. (verb) appear to move downward

• decline

11. (verb) fall heavily or suddenly; decline markedly

• drop

12. (verb) fall or sink heavily

• break
• cave in
• collapse
• fall in
• founder
• give
• give way

13. (verb) embed deeply

• embed
• engraft
• imbed
• implant
• plant

1. (noun) (technology) a process that acts to absorb or remove energy or a substance from a system

• applied science
• engineering
• engineering science
• technology

1. (noun) plumbing fixture consisting of a water basin fixed to a wall or floor and having a drainpipe

• basin
• lavatory
• washbasin
• washbowl
• washstand
• kitchen sink

2. (noun) (technology) a process that acts to absorb or remove energy or a substance from a system

• heat sink

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

• droop
• flag
• sag
• swag
• drop open
• fall open
• sag
• sag down

4. (verb) cause to sink

• settle

5. (verb) go under,

• founder
• settle
• subside
• submerge
• submerse

6. (verb) appear to move downward

• subside

7. (verb) embed deeply

• countersink
• set

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

• drop
• drop cloth
• drop curtain

2. (verb) pass into a specified state or condition

• passage
• transition

3. (verb) go under,

• sinker
• sinking

4. (verb) fall heavily or suddenly; decline markedly

• depression
• economic crisis
• slump
• drop-off
• drop-off
• falling off
• falling off
• falloff
• falloff
• slack
• slack
• slump
• slump

1. (verb) go under,

• filter
• percolate
• permeate
• sink in

1. (noun) (technology) a process that acts to absorb or remove energy or a substance from a system

• source

2. (verb) go under,

• float
• swim