■ verb
1》 become less intense, violent, or severe.
↘( ~ into ) give way to (an overwhelming feeling).
2》 (of water) go down to a lower or the normal level.
↘(of a swelling) reduce until gone.
3》 (of a building) sink lower into the ground.
↘(of the ground) cave in; sink.
↘ informal sink into a sitting, kneeling, or lying position.
Origin
C17: from L. ~re , from sub- 'below' + sidere 'settle'.