The definition of a slum is a house or a neighborhood that is in poor condition and that is generally considered unsafe and not nice to live or be in.(noun)
To slum is to engage in behavior or hang out with people below your social class.(verb)
When a rich person goes to spend time in a really poor neighborhood, this is an example of a time when he slums.
See slum in Webster's New World College Dictionary
Origin: c. 1800 < cant: orig. sense, a room < ?
See slum in American Heritage Dictionary 4
Origin: Origin unknown.
Learn more about slum