sink in WordNet English dictionary

1. embed deeply
   "She sank her fingers into the soft sand"; "He buried his head in her lap"
   bury  sink 
   
2. appear to move downward
   "The sun dipped below the horizon"; "The setting sun sank below the tree line"
   dip  sink 
   
3. fall or descend to a lower place or level
   "He sank to his knees"
   sink  drop  drop down 
   
4. fall heavily or suddenly; decline markedly
   "The real estate market fell off"
   slump  fall off  sink 
   
5. go under, "The raft sank and its occupants drowned"
   sink  settle  go down  go under 
   
6. pass into a specified state or condition
   "He sank into nirvana"
   sink  pass  lapse 
   
7. cause to sink
   "The Japanese sank American ships in Pearl Harbor"
   sink 
   
8. fall or sink heavily
   "He slumped onto the couch"; "My spirits sank"
   slump  slide down  sink 
   
9. descend into or as if into some soft substance or place
   "He sank into bed"; "She subsided into the chair"
   sink  subside 
   

1. a covered cistern; waste water and sewage flow into it
   cesspool  cesspit  sink  sump 
   
2. plumbing fixture consisting of a water basin fixed to a wall or floor and having a drainpipe
   sink 
   
3. 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  sink  swallow hole 
   
4. (technology) a process that acts to absorb or remove energy or a substance from a system
   "the ocean is a sink for carbon dioxide"
   sink