subside

Verb

• descend into or as if into some soft substance or place
  • He sank into bed
    
  • She subsided into the chair
    

• sink down or precipitate
  • the mud subsides when the waters become calm
    

• sink to a lower level or form a depression
  • the valleys subside
    

• wear off or die down
  • The pain subsided
    

Related words

• Synonyms: 
  sink , settle , lessen