un·der·class 
/ˈʌndɚˌklæs, Brit ˈʌndəˌklɑ:s/ noun
plural un·der·class·es /ˈʌndɚˌklæs, Brit ˈʌndəˌklɑ:s/ noun [count] : a social class made up of people who are very poor and have very little power or chance to improve their lives : the lowest social class — usually singular ▪ the suffering of the underclass
