A mourner is someone who is attending a funeral

Funeral

A funeral is a ceremony for celebrating, sanctifying, or remembering the life of a person who has died. Funerary customs comprise the complex of beliefs and practices used by a culture to remember the dead, from interment itself, to various monuments, prayers, and rituals undertaken in their honor...

 or who is otherwise recognized as in a period of grief

Grief

Grief is a multi-faceted response to loss, particularly to the loss of someone or something to which a bond was formed. Although conventionally focused on the emotional response to loss, it also has physical, cognitive, behavioral, social, and philosophical dimensions...

 and mourning

Mourning

Mourning is, in the simplest sense, synonymous with grief over the death of someone. The word is also used to describe a cultural complex of behaviours in which the bereaved participate or are expected to participate...

 prescribed either by religious law or by popular custom. Many cultures expect mourners to curtail certain activities, usually those considered frivolous or that are accompanied by expressions of joy.

Historically, some cultures have employed professional mourners

Professional mourning

Professional mourning or paid mourning is a mostly historical occupation practiced in Near Eastern cultures and many other parts of the world. Professional mourners are compensated to lament or deliver a eulogy. Mentioned in the Bible, the occupation is widely invoked in literature, from the...

 to make a public showing of grief to honor the deceased (particularly those in the Near East

Near East

The Near East is a geographical term that covers different countries for geographers, archeologists, and historians, on the one hand, and for political scientists, economists, and journalists, on the other...

).