Socio-economic class and Underclass

Socio-economic class noun - People having the same social, economic, or educational status.

Underclass and socio-economic class are semantically related. In some cases you can replace term "Underclass" with "Socio-economic class", this terms are similar.

Underclass noun - The social class lowest in the social hierarchy.

Socio-economic class and underclass are semantically related. Sometimes you can use "Socio-economic class" instead a noun "Underclass".