to wail in mourning: to perform the loud, public lament for the dead, chest-beating and crying aloud.
This is not quiet, private sadness but the visible, audible act of mourning. It is the funeral wail, often paired with beating the breast, tearing clothes, and wearing rough sackcloth. The related noun from this same root names the wailing itself, the loud lament that fills the air at a burial.
Most often the word describes grieving a specific person who has died: Abraham for Sarah, David and his men for Saul and Jonathan, all Israel for the prophet Samuel. To refuse or be denied this wailing was a horror. The prophets warn that people will die unmourned and unburied, their bodies left in the open, and a king is threatened with a burial that no one laments.
The same public wailing is also turned toward disaster. When a land is ruined, a city judged, or the offerings cut off, people take up this same cry of grief, as if lamenting a death. So the word runs from the graveside to the ruined field, but it is always the outward act of loud lament, never mere inner sorrow.